diff --git a/2020/13.py b/2020/13.py
new file mode 100755
index 0000000..4607a4f
--- /dev/null
+++ b/2020/13.py
@@ -0,0 +1,75 @@
+#!/usr/bin/env python
+
+from aoc import get_input # AoC
+import re # regex
+
+data = get_input(13).splitlines()
+
+time = int(data[0])
+
+busses = []
+for busid in data[1].split(","):
+    if(busid != "x"):
+        busses.append(int(busid))
+    # else:
+    #     busses.append(busid)
+
+##busses.sort()
+
+
+def getTimestamp(busid, i):
+    return busid * i
+
+
+# bustimes = dict()
+
+# for busid in busses:
+#     print("checking ", busid)
+#     i = 0
+#     bustimes[busid] = []
+#     while True:
+#         timestamp = getTimestamp(busid, i)
+#         bustimes[busid].append(timestamp)
+
+#         if(timestamp > time):
+#             break
+#         else:
+#             i += 1
+#             continue
+
+# waittimes = dict()
+# for busid, t in bustimes.items():
+#     high = max(t)
+#     waittimes[busid] = high - time
+
+# bestbusid = min(waittimes, key=waittimes.get)
+
+# thing = bestbusid * waittimes[bestbusid]
+
+# print(bestbusid, thing)
+
+
+bus = dict()
+i = 0
+for busid in data[1].split(","):
+    if(busid != "x"):
+        bus[i] = int(busid)
+
+    i += 1
+
+
+minindex, maxindex = 0, len(bus) - 1
+from sympy.ntheory.modular import crt
+
+thing = []
+buss = []
+for i, busid in bus.items():
+    thing.append(i)
+    buss.append(busid)
+
+print(bus, buss, thing)
+hello = crt(buss, thing)
+print(hello)
+
+thething = hello[1] - hello[0]
+print(thething)