diff --git a/day25-input.txt b/day25-input.txt
new file mode 100644
index 0000000..db2a942
--- /dev/null
+++ b/day25-input.txt
@@ -0,0 +1,129 @@
+1-012=0=2=--12
+11=
+1=--000111=01-0
+201-12=0211--
+110-=010-01--02
+11021==---22-1
+122001
+1--0
+2-=2
+22=02==01=0-2-011
+12-2-00-11
+20=0-2102=-01
+1102=
+122--0-112221
+11=00-2=201-22=-=
+10-02==210--=0
+2=220-02=1202
+1=--0-
+2-122==
+10-=00
+1=001-22==1
+1=121022122-1--0
+11-
+2=0-1-0-1
+1=-0221-==
+1-==-0--1012
+1--02=-01=020110=
+2-0212==1--=2=
+112
+1=-=1=0012201
+1==-
+1=02-2=012-=2--=--
+1=220-1=0--=1
+10-=
+1-=22-111=211
+11--==21==202
+20-
+1=-1=02=0=1===0-210
+1==-0=010
+1=-2=-=2-01-102102=
+110-==0=2=-==-2-10
+12200=--21-
+21-=1-=1-2-
+111-==2=2
+210=-0-02=-0=11
+10-1
+1-0=011
+20=10=001-
+2-0=0-=1121=---2-0
+22-1=2=0202
+21=2201020211=2
+1-110=
+21=22=0-=1==121
+1==-=01
+1-1=1012==1
+1-01===1=--21
+1==
+2-=
+200=202121--0122
+1-02
+1=21=-12-0-
+2-=10
+121=-20=0200=02==1
+101=2-2102-0-02=
+1===11
+22==0
+22-21==-2-1220=10
+1==2120--1-=
+1=11-2=-110100002200
+2211=2=-=-=01-01
+1==-010==-=2-=
+2=0=2
+11-100-21=
+11=1=-1=0
+2=2--1=2
+1-0==1=2-211=1
+1-2=-202011211
+10=-==-00-1==01
+1-=2122==
+112=-012
+12==-0=
+1122-0=0
+1=2=0
+2===-0=-0-0
+1212
+202
+1==1
+2111=1=000221-=-2=-
+210111=2=0-1==-
+1===00=
+22=22=-1-==2-==
+102--1=-1=222
+2=--=--0-2
+11-02=201101=2
+1=
+12--112-=0=
+10====0=220
+100020002=-0=02-1-
+101
+1=1-112-=
+2022-02
+22201212
+21221201010210-1-
+1-=1=-121-0-221-10
+1=212=01--10-==
+12-0=2121=21-2
+111-2-00
+1=20=202--
+2-==2=--2-2101002
+111-12=00
+1=0===2=
+12=-2020=1=2012
+2=
+1-02---
+221---2122212
+10=-20002=20-22
+2010-220
+12
+2=0-=221
+10011=0
+1-20--=1=1-=1
+1=1
+1=0202-2-1=20-2-
+101=--0-=-010-=
+1=12=--
+2=2111=
+1=0-2=2120002=0
+10-1=0---10=-20=010
+20-121===--=2-=111
diff --git a/day25-scratch.lisp b/day25-scratch.lisp
new file mode 100644
index 0000000..c98834e
--- /dev/null
+++ b/day25-scratch.lisp
@@ -0,0 +1,96 @@
+;; https://adventofcode.com/2022/day/25
+(in-package :day-25)
+
+;; so. from decimal to SNAFU and back...
+;; or maybe direct sum in snafu?
+;;
+;; at least 16 digits in my input
+
+(parse-integer (format nil "~a" '1))    ; kek
+;; would rather have hashmap then? or array, i guess
+;; no? list? alist is list of cons cells, no?
+;; from SNAFU should be easier
+;; 1=-0-2
+(defparameter *test-snafu*
+  '((5 . 1) (4 . -2) (3 . -1) (2 . 0) (1 . -1) (0 . 2)))
+(assoc 4 *test-snafu*)
+(alexandria:assoc-value *test-snafu* 4)
+
+(loop
+  for (pow . mul) in *test-snafu*
+  sum (* mul (expt 5 pow)))
+
+(exp 2)                                 ; e^2
+(expt 5 2)                              ; 5^2
+
+;; now i want to parse snafu number, right?
+;; reverse, start with power 0 yeah, i guess
+;; 1-12
+
+(mul-to-char 1)
+(mul-to-char -1)
+(mul-to-char -2)
+(char-to-mul #\=)
+(coerce )
+
+(let ((str "1-12"))
+  (loop
+    for char across (reverse (coerce str 'array))
+    for pow from 0
+    collect (cons pow (char-to-mul char))))
+
+(snafu-to-dec (read-snafu "1-12"))
+
+;; but last thing i want is decimal to snafu.
+;; and that's ugh.
+;; i could decode into 5 base system, maybe even automatically,
+;; then parse into powers of 5 written in 0 - 5
+
+(format t "print in base/radix 5 - ~5R ~5R ~5R ~5R ~5R " 4 5 6 7 8 9)
+;; i think this works.
+;; now i could parse this into amounts of powers of 5.
+;; but then i'd still need to go from 0..5 to -2..2
+;;
+;; if in pow_k we have >2
+;; we can +1 to higher power pow_k+1
+;; and to balance -5 in pow_k
+
+(decimal-to-pows-5 1747)                ; yeah, maybe good, yes
+(- (char-code #\1) (char-code #\0))
+(- (char-code #\4) (char-code #\0))
+(- (char-code #\6) (char-code #\0))
+(- (char-code #\7) (char-code #\0))
+(- (char-code #\9) (char-code #\0))
+
+;; and now - modify multipliers of the powers.
+;; loop from 0 to (1- length) over all powers.
+;;
+
+(defparameter *test-snafu*
+  '((5 . 1) (4 . -2) (3 . -1) (2 . 0) (1 . -1) (0 . 2)))
+(setf  (cdr (assoc 4 *test-snafu*)) 6)
+(setf  (cdr (assoc 6 *test-snafu*)) 6)
+(setf  (assoc 6 *test-snafu*) '(6 . 2))
+(alexandria:assoc-value *test-snafu* 4)
+
+(print (decimal-to-pows-5 1747))
+;; ((0 . 2) (1 . 4) (2 . 4) (3 . 3) (4 . 2))
+(print (pows-5-to-snafu (decimal-to-pows-5 1747)))
+;; ((0 . 2) (1 . -1) (2 . 0) (3 . -1) (4 . -2) (5 . 1))
+;; ((0 . 2) (1 . 4) (2 . 4) (3 . 3) (4 . 2))
+;; ((0 . -3) (1 . 0) (2 . 5) (3 . 3) (4 . 2))
+
+(coerce (list #\a #\1 #\- #\e) 'string)
+
+(snafu-to-dec (pows-5-to-snafu (decimal-to-pows-5 1747)))
+(snafu-pows-print (pows-5-to-snafu (decimal-to-pows-5 1747)))
+;; yeah
+
+(loop
+  for line in (uiop:read-file-lines "day25-test.txt")
+  for dec = (snafu-to-dec (read-snafu line))
+  summing dec into the-sum
+  finally (return (snafu-pows-print (decimal-to-snafu the-sum))))
+
+;; (part-1-calc "day25-test.txt")
+;; (print (part-1-calc "day25-input.txt"))
diff --git a/day25-test.txt b/day25-test.txt
new file mode 100644
index 0000000..027aeec
--- /dev/null
+++ b/day25-test.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/day25.lisp b/day25.lisp
new file mode 100644
index 0000000..ef20c7a
--- /dev/null
+++ b/day25.lisp
@@ -0,0 +1,68 @@
+;; https://adventofcode.com/2022/day/25
+(defpackage :day-25
+  (:use :cl))
+
+(in-package :day-25)
+(ql:quickload 'alexandria)
+
+(defun snafu-to-dec (snafu-alist)
+  (loop
+  for (pow . mul) in snafu-alist
+  sum (* mul (expt 5 pow))))
+
+;; let's do that as alist as well?
+(defparameter *snafu-char-to-mul*
+  '((#\2 . 2)
+    (#\1  . 1)
+    (#\0  . 0)
+    (#\-  . -1)
+    (#\=  . -2)))
+
+(defun char-to-mul (char)
+  (alexandria:assoc-value *snafu-char-to-mul* char))
+(defun mul-to-char (n)
+  (alexandria:rassoc-value *snafu-char-to-mul* n))
+
+;; into the alist power representation
+(defun read-snafu (str)
+  (loop
+    for char across (reverse (coerce str 'array))
+    for pow from 0
+    collect (cons pow (char-to-mul char))))
+
+(defun decimal-to-pows-5 (num)
+  (let ((str (format nil "~5R" num)))
+    (loop
+      for char across (reverse (coerce str 'array))
+      for pow from 0
+      ;; do (print char)
+      collect (cons pow (- (char-code char) (char-code #\0))))))
+
+(defun pows-5-to-snafu (pows-5)
+  (let ((copied-list (copy-alist pows-5)))
+    (loop
+      for pow from 0 below (length pows-5)
+      when (> (alexandria:assoc-value copied-list pow) 2)
+        do (progn
+             (incf (cdr (assoc pow copied-list)) -5)
+             (when (not (assoc (1+ pow) copied-list))
+               (push (cons (1+ pow) 0) copied-list))
+             (incf (cdr (assoc (1+ pow) copied-list)))))
+    copied-list))
+
+(defun snafu-pows-print (snafu-alist)
+  (coerce  (loop
+             for pow from (1- (length snafu-alist)) downto 0
+             collect (mul-to-char (alexandria:assoc-value snafu-alist pow))
+             )
+           'string))
+
+(defun decimal-to-snafu (num)
+  (pows-5-to-snafu (decimal-to-pows-5 num)))
+
+(defun part-1-calc (filename)
+ (loop
+  for line in (uiop:read-file-lines filename)
+  for dec = (snafu-to-dec (read-snafu line))
+  summing dec into the-sum
+  finally (return (snafu-pows-print (decimal-to-snafu the-sum)))) )