f = [1, 1]
while f[-1] < 10**15:
    f.append(f[-1] + f[-2])

A = list(reversed([int(input()) for _ in range(5)]))

ans = 0
for l in range(1, 6):
    for j in range(len(f)):
        if j + l > len(f):
            continue
        if A[:l] == f[j:j+l]:
            ans = l

print(ans)