diff --git a/2020/day13.py b/2020/day13.py
new file mode 100644
index 0000000..ef7ec99
--- /dev/null
+++ b/2020/day13.py
@@ -0,0 +1,11 @@
+input_t = 1002392  # Short input so we'll just hardcode
+input_busIDs = "23,x,x,x,x,x,x,x,x,x,x,x,x,41,x,x,x,37,x,x,x,x,x,421,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,17,x,19,x,x,x,x,x,x,x,x,x,29,x,487,x,x,x,x,x,x,x,x,x,x,x,x,13"
+ids = {int(x) for x in input_busIDs.split(',') if x != 'x'}
+
+next_arrivals = {x: x*(-(-input_t//x)) for x in ids}  # -(-x//y) is ceil(x/y)
+id, t = min(next_arrivals.items(), key=lambda x: x[1])
+print(f'Part 1: Next bus is Bus {id} at t={t} -> {id*(t-input_t)}')
+
+from sympy.ntheory.modular import crt
+pairs = [(i,int(v)) for i,v in enumerate(input_busIDs.split(',')) if v != 'x']
+print(f'Part 2: t = {crt([id for time,id in pairs], [-time for time,id in pairs])[0]}')