diff --git a/day25/input.txt b/day25/input.txt
new file mode 100644
index 0000000..ce170c3
--- /dev/null
+++ b/day25/input.txt
@@ -0,0 +1,111 @@
+1=021=20---11-1=1
+222==-=1-2=-11-11
+1010==0=0=1--=1
+2
+1122=
+2222==2222-2--10
+100=-2-002=
+12221-2-10-=1=
+1-=211000=221-1
+2=--12==11221-2-002
+1101==-01===01=
+220=0=-2-1-0===10=2
+2-0-
+1=-12=2==
+1-=-02==-1
+100-0-11--02--0=-
+1==0-1220011=-
+21
+1102-22==
+222
+1==0=22-0--011-0
+1020
+2==2-102
+1010-02==02=
+1=1
+2=010==12022=
+1=-22001-2=
+101=2-201122111
+1=-0021211-1-1-1202
+2-22-2
+1212002==1
+2=-0-
+1-1==1122110100
+1--020-2-=-0-21--
+2=22-21220022==1=
+1=-00-121-20-2122
+1-==-00
+20=21=0
+20-02-0-=-==-=22
+1120==-2
+2=--0-0-000201=101
+1---=02=21
+1-011
+211-2112=20--2
+1=-
+1=--=021
+1-1-122200==1-1111
+11001-
+200=200
+1===21=1-2
+1===10
+2=22
+10-110210=01112-
+2121=1=2=-201-
+1---2=-0=-
+211-120---000=-0-
+1-
+1-101-2=01020=-0=
+112-12--0=12=12--
+1-0-=2--=--12=20
+1=0=-121
+1000122-210--011200
+120==-1-=01
+1=2=1--
+101-1=--2-
+2=
+2--10
+2201020-=2-
+1===2001-1=0=
+222=-2---2=112
+2010=-22=012=202=
+111
+1-2112=0200=1
+2=02211=2
+2-121
+1----12=-2011
+2==0
+112
+22=0==1-1=
+1-20=0-
+1=110211-022201222
+20
+1-111
+1=-=022011=2=2=1
+1-02122
+2-1
+1-2-=2-0=0---
+1-20
+1=1=102
+1=1=0--1
+11222-==0101-
+2122100=0
+2011==12-10
+210--121-0=
+22121=01=0=-=-=-==
+10-0-=1-12
+2-2=21
+1=1-0-0-
+10020
+10-0-0120=211-2-
+1-==10-0-==001201-
+1-0
+21=00202002-0
+1-1=2021
+11=1==1=0
+1=102-1=-20-0
+2=100-12-0=
+1=0
+1--=
+12=212110200-
+222002100
diff --git a/day25/snafu b/day25/snafu
new file mode 100755
index 0000000..55139cf
Binary files /dev/null and b/day25/snafu differ
diff --git a/day25/snafu.c b/day25/snafu.c
new file mode 100644
index 0000000..95ce479
--- /dev/null
+++ b/day25/snafu.c
@@ -0,0 +1,102 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define BUFFER_SIZE 64
+#define MAGIC_NUMBER 5
+
+long powNum(long, long);
+long snafu_to_human(char*, int);
+void human_to_snafu(char*, long);
+
+int main() {
+    char buf[BUFFER_SIZE], *p, c;
+    memset(buf, 0, BUFFER_SIZE);
+    p = buf;
+    long sum = 0;
+
+    while ((c = getchar()) != EOF) {
+        *p++ = c;
+        if (c == '\n') {
+            sum += snafu_to_human(p-2, p-buf);
+            memset(buf, 0, BUFFER_SIZE);
+            p = buf;
+        }
+    }
+
+    printf("Sum in decimal: %li\n", sum);
+    char snafu[64];
+    memset(snafu, 0, 64);
+    human_to_snafu(snafu, sum);
+    printf("Sum in SNAFU: %s\n", snafu);
+}
+
+long powNum(long b, long e) {
+    long result = 1;
+    for (int i = 0; i < e; i++) {
+        result *= b;
+    }
+
+    return result;
+}
+
+long snafu_to_human(char* p, int len) {
+    long result = 0;
+    for (int i = 0; i < len; i++) {
+        switch(*(p-i)) {
+            case '0':
+                break;
+            case '1':
+                result += powNum(MAGIC_NUMBER, i);
+                break;
+            case '2':
+                result += 2*powNum(MAGIC_NUMBER, i);
+                break;
+            case '-':
+                result += -powNum(MAGIC_NUMBER, i);
+                break;
+            case '=':
+                result += -2*powNum(MAGIC_NUMBER, i);
+                break;
+        }
+    }
+
+    return result;
+}
+
+void human_to_snafu(char* p, long decimal) {
+    char buf[64], *q;
+    memset(buf, 0, 64);
+
+    long num = decimal;
+    int len = 0;
+    int remainder = 0;
+
+    while (num != 0) {
+        int numeric = num % MAGIC_NUMBER;
+        num /= MAGIC_NUMBER;
+        numeric += remainder;
+        remainder = 0;
+        if (numeric > 2) {
+            remainder = 1;
+            numeric = numeric - MAGIC_NUMBER;
+        }
+        if (numeric == -1) {
+            buf[len] = '-';
+        } else if (numeric == -2) {
+            buf[len] = '=';
+        } else {
+            buf[len] = '0' + numeric;
+        }
+        len++;
+    }
+
+    if (remainder) {
+        buf[len] = '1';
+        len++;
+    }
+
+    for (int i = 0; i <= len; i++) {
+        *(p+len-i-1) = buf[i];
+    }
+}