diff --git a/13/a.py b/13/a.py
new file mode 100644
index 0000000..7244e71
--- /dev/null
+++ b/13/a.py
@@ -0,0 +1,35 @@
+import math
+
+d = [ x.split(',') for x in open('input').read().splitlines() ]
+
+def a(d):    #To be honest, I could've done this way quicker manually and got on the leaderboard. Formula is x - ID mod x for the waiting time
+    x = int(d[0][0])
+    ids = [ int(x) for x in d[1] if x != 'x' ] 
+    delta = { id:(id - (x % id)) for id in ids if ( x := int(d[0][0]) )}
+    minId = min(delta, key=delta.get)
+    return (delta[minId]*minId)
+
+print(a(d))
+
+def b(d):
+    d = [ [-y,int(d[y])] for y in {i:d[i] for i in range(len(d))} if d[y] != 'x']
+    [ print(x) for x in d ] # generate numbers
+
+
+# I'm a math noob, so I just saw what everyone else is talking about and found this chinese remainder theorem.
+# Why does this work? I DONT KNOW.
+# I'll probably learn this when I get some formal CS education.
+# Used a solver for that.
+
+# x = 760171380521445
+# x ≡ 0 mod 17 => x = n*17+0
+# x ≡ −7 mod 41 => x = n*41-7 ???   # -7 because of 
+# x ≡ −17 mod 643
+# x ≡ −25 mod 23
+# x ≡ −30 mod 13
+# x ≡ −46 mod 29
+# x ≡ −48 mod 433
+# x ≡ −54 mod 37
+# x ≡ −67 mod 19
+ 
+b(d[1])