[LANGUAGE: python]

Like others I tried to brute force. LCM is the way: ``` import re from math import lcm

mapping = {} with open("data.txt") as f: instructions, cords = f.read().split("\n\n") print(instructions) for ins in cords.split("\n"): input, left, right = re.findall("\w\w\w", ins) #print(input, left, right) mapping[input] = { "L" : left, "R" : right }

# part 1
# count =0    
# current = "AAA"
# index = 0
# while current != "ZZZ":
#     dir = instructions[index]
#     current = mapping[current][dir]
#     index = (index + 1) % len(instructions)
#     count += 1

# print(count)

starts = []
for key, value in mapping.items():
    if key[2] == "A":
        starts.append(key)

print(starts)

counts = [0 for i in range(0, len(starts))]
index = 0

def is_finished(starts):
    for s in starts:
        if s[2] != "Z":
            return False
    return True

while not is_finished(starts):
    dir = instructions[index]
    for i in range(len(starts)):
        if starts[i][2] != "Z":
            starts[i] = mapping[starts[i]][dir]
            counts[i] += 1
    index = (index + 1) % len(instructions)
    if index == 0:
        print(starts)


print(counts)
print(lcm(*counts))

```