diff --git a/README.md b/README.md
index 66cb977..943a4e4 100644
--- a/README.md
+++ b/README.md
@@ -6,30 +6,32 @@ My goal is to solve each puzzle on the day it was posted. Also I want to create
 
 I use python 3.11 without any libraries beyond the standard.
 
-| Day | Time      | Rank  | Score | Time     | Rank  | Score |
-| --- | --------- | ----- | ----- | -------- | ----- | ----- |
-| 24  |     >24h  |11497  |    0  |     >24h | 11666 |     0 |
-| 23  |     >24h  |13621  |    0  |     >24h | 13384 |     0 |
-| 22  | 01:30:48  | 2540  |    0  |     >24h | 10636 |     0 |
-| 21  | 00:20:57  | 2178  |    0  | 01:10:59 |  2175 |     0 |
-| 20  | 11:19:34  | 9421  |    0  | 11:24:45 |  8501 |     0 |
-| 18  | 00:31:49  | 3269  |    0  | 01:51:15 |  3121 |     0 |
-| 17  | 01:21:11  | 2058  |    0  | 02:42:45 |  1665 |     0 |
-| 16  | 02:44:20  | 2611  |    0  |     >24h | 10509 |     0 |
-| 15  | 00:58:10  | 3963  |    0  | 02:26:22 |  4011 |     0 |
-| 14  | 00:58:39  | 4431  |    0  | 01:18:15 |  4620 |     0 |
-| 13  | 01:23:44  | 5522  |    0  | 01:45:59 |  5610 |     0 |
-| 12  | 01:43:14  | 6571  |    0  | 01:51:15 |  6246 |     0 |
-| 11  | 00:56:44  | 5414  |    0  | 02:42:24 |  7558 |     0 |
-| 10  | 00:38:16  | 7637  |    0  | 01:16:55 |  7961 |     0 |
-|  9  | 00:54:18  | 7719  |    0  | 01:07:37 |  4901 |     0 |
-|  8  | 00:41:51  | 7831  |    0  | 00:59:27 |  6325 |     0 |
-|  7  | 00:34:59  | 2683  |    0  | 00:45:45 |  2943 |     0 |
-|  6  | 00:14:52  | 9153  |    0  | 00:17:06 |  8413 |     0 |
-|  5  | 01:01:27  |11570  |    0  | 01:05:20 | 10701 |     0 |
-|  4  | 00:12:09  | 5789  |    0  | 00:16:03 |  5187 |     0 |
-|  3  | 00:47:15  |13278  |    0  | 01:07:44 | 12947 |     0 |
-|  2  | 00:21:47  | 8874  |    0  | 00:36:49 |  9949 |     0 |
-|  1  | 00:10:25  | 5460  |    0  | 00:14:20 |  5269 |     0 |
+| Day | Time      |  Rank  | Score | Time     | Rank  | Score |
+| --- | --------- |  ----- | ----- | -------- | ----- | ----- |
+| 25  |     >24h  | 14695  |    0  |     >24h |  9050 |     0 |
+| 24  |     >24h  | 11497  |    0  |     >24h | 11666 |     0 |
+| 23  |     >24h  | 13621  |    0  |     >24h | 13384 |     0 |
+| 22  | 01:30:48  |  2540  |    0  |     >24h | 10636 |     0 |
+| 21  | 00:20:57  |  2178  |    0  | 01:10:59 |  2175 |     0 |
+| 20  | 11:19:34  |  9421  |    0  | 11:24:45 |  8501 |     0 |
+| 19  |     >24h  | 14445  |    0  |     >24h | 13544 |     0 |
+| 18  | 00:31:49  |  3269  |    0  | 01:51:15 |  3121 |     0 |
+| 17  | 01:21:11  |  2058  |    0  | 02:42:45 |  1665 |     0 |
+| 16  | 02:44:20  |  2611  |    0  |     >24h | 10509 |     0 |
+| 15  | 00:58:10  |  3963  |    0  | 02:26:22 |  4011 |     0 |
+| 14  | 00:58:39  |  4431  |    0  | 01:18:15 |  4620 |     0 |
+| 13  | 01:23:44  |  5522  |    0  | 01:45:59 |  5610 |     0 |
+| 12  | 01:43:14  |  6571  |    0  | 01:51:15 |  6246 |     0 |
+| 11  | 00:56:44  |  5414  |    0  | 02:42:24 |  7558 |     0 |
+| 10  | 00:38:16  |  7637  |    0  | 01:16:55 |  7961 |     0 |
+|  9  | 00:54:18  |  7719  |    0  | 01:07:37 |  4901 |     0 |
+|  8  | 00:41:51  |  7831  |    0  | 00:59:27 |  6325 |     0 |
+|  7  | 00:34:59  |  2683  |    0  | 00:45:45 |  2943 |     0 |
+|  6  | 00:14:52  |  9153  |    0  | 00:17:06 |  8413 |     0 |
+|  5  | 01:01:27  | 11570  |    0  | 01:05:20 | 10701 |     0 |
+|  4  | 00:12:09  |  5789  |    0  | 00:16:03 |  5187 |     0 |
+|  3  | 00:47:15  | 13278  |    0  | 01:07:44 | 12947 |     0 |
+|  2  | 00:21:47  |  8874  |    0  | 00:36:49 |  9949 |     0 |
+|  1  | 00:10:25  |  5460  |    0  | 00:14:20 |  5269 |     0 |
 
 All code is published under the [Unlicense](https://unlicense.org/)
\ No newline at end of file
diff --git a/advent/days/day25/__init__.py b/advent/days/day25/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/advent/days/day25/data/example01.txt b/advent/days/day25/data/example01.txt
new file mode 100644
index 0000000..027aeec
--- /dev/null
+++ b/advent/days/day25/data/example01.txt
@@ -0,0 +1,13 @@
+1=-0-2
+12111
+2=0=
+21
+2=01
+111
+20012
+112
+1=-1=
+1-12
+12
+1=
+122
diff --git a/advent/days/day25/data/input.txt b/advent/days/day25/data/input.txt
new file mode 100644
index 0000000..b406fc1
--- /dev/null
+++ b/advent/days/day25/data/input.txt
@@ -0,0 +1,143 @@
+1=0=01=0=2111-1211
+1==21=
+20--
+1-=1200=-=0
+211==12=2=0111==
+2=-10
+1221=221=0-1=-
+12=02=-12020=12=01-
+12112101
+20
+120120=21=1002-1
+10==1-02=1
+1=11200001-=--
+1=222-1=012=2
+20===1-1102-=
+1020
+102=-==-=2-
+112-2112-00012-
+1010=--121
+202022=-=2-22=
+122==1=1020011=-00
+10212==-0
+2=--12020=1-0=-2=-
+1110-1-2
+20==210221=-21--12
+1=-02--=22=-122
+2=-=0=00=1--1-2=--
+2==2==2-
+2=12=1
+2=01=
+202=20202-000
+1=0-=020021022012
+2=0-011-=2=-0-=21
+1=211
+1-=1=11=--010=---
+1000020-12==
+2-=122-1211-0=
+10=2220122012
+2=21-01=212
+10111==2=2-12
+111
+1=2---2211=2011=--
+1--=0000=1-020
+2=02-=-
+1-011=
+12020-0=-1-220100
+2-==000=21=1
+2-0100000-12-2-=
+1-=1
+1221=2-1==02-=202
+200
+122-2-0
+10=2101-22
+1==-120-1
+2=2=2=-11--==-==
+2111-=2=-=-2
+1--
+1-0=10-0112-12=
+10=
+2=01=1=-=20=
+1=
+1211-2=-1=
+222=
+122=2-1-0
+1-2=20-=02122-1
+1==-=2===0-=1100--11
+12-0=201=10=-=
+1=01=2=22-2-1-1
+120==222100=0
+11=-=--12=2-1101
+102=1221=---0==021
+2-=-2=202-=-==
+100=1=02020-221=
+1=0=-220=
+1001-
+20==2==1-1
+1=2-2=2=-12=
+10=0--2
+10-202-2002=22=
+2=2=
+1-011=0=-12---
+1002220
+2=
+1--=2---111
+222==2
+11100
+1=0=201
+1--02-
+1=11-==0=021
+1-=00=
+1==12-20-=002001=
+1=0=-=21-
+1000-1=0-0=1=01-2-
+2==
+1-0
+1=101-0-1
+1=0=
+11=2==-0-2202-0=
+10-0=0=1-002
+1-=0210=01120-
+1112=2-0-2=-01
+1-1=022=21
+2=1-2--120
+10002--0=220-0-2=12
+11002102100
+11000-2-12
+120=-==1-2-=
+21
+11
+2=121-
+1==
+1=-
+1-=--2=-
+2=-10-=0
+2200-1-
+2=21-1200==
+1-102210=002=--112
+1-10
+122=202=201-=-10-1
+2212121=02102
+21=2-211=-1-20-
+101-=01-1
+200012112=
+22=21201=22
+1-1212=1-=1
+1212-==1=01
+22==--=
+1=-2-1-==020-10-=
+1=1210=--00
+1=--=1=
+2010111-00111-2=2
+11=21-0=2-01
+21=
+1=-0-220
+102-=0
+1=---0-
+1-1122-=121222--0
+10110=1-20--1-1
+20=--21220-=
+1=---22-
+2-000===1101=
+20-
+10==
diff --git a/advent/days/day25/solution.py b/advent/days/day25/solution.py
new file mode 100644
index 0000000..db89abc
--- /dev/null
+++ b/advent/days/day25/solution.py
@@ -0,0 +1,33 @@
+from __future__ import annotations
+
+from typing import Iterator
+
+day_num = 25
+
+
+def part1(lines: Iterator[str]) -> str:
+    snafu = sum(from_snafu(line) for line in lines)
+    return to_snafu(snafu)
+
+
+def part2(lines: Iterator[str]) -> None:
+    return None
+
+
+SNAFU = "=-012"
+
+
+def from_snafu(line: str) -> int:
+    result = 0
+    for char in line:
+        result = result * 5 + SNAFU.index(char) - 2
+    return result
+
+
+def to_snafu(number: int) -> str:
+    result = ""
+    while number > 0:
+        mod = (number + 2) % 5
+        result = SNAFU[mod] + result
+        number = (number - mod + 2) // 5
+    return result
diff --git a/advent/days/day25/test_solution.py b/advent/days/day25/test_solution.py
new file mode 100644
index 0000000..435633d
--- /dev/null
+++ b/advent/days/day25/test_solution.py
@@ -0,0 +1,31 @@
+from advent.common import input
+
+from .solution import day_num, part1, part2, from_snafu, to_snafu
+
+
+def test_part1():
+    lines = input.read_lines(day_num, 'example01.txt')
+    expected = "2=-1=0"
+    result = part1(lines)
+    assert result == expected
+
+
+def test_part2():
+    lines = input.read_lines(day_num, 'example01.txt')
+    expected = None
+    result = part2(lines)
+    assert result == expected
+
+
+def test_976():
+    input = "2=-01"
+    expected = 976
+    result = from_snafu(input)
+    assert result == expected
+
+
+def test_4890():
+    input = 4890
+    expected = "2=-1=0"
+    result = to_snafu(input)
+    assert result == expected