F = [1,1]
for i in range(71):
    F.append(F[-1] + F[-2])
X = [int(input()) for _ in range(5)][::-1]

if X[0] not in F:
    print(0)
    exit()
if X[0] == 1:
    if X[1] == 1:
        st = 0
    else:
        st = 1
else:
    st = F.index(X[0])
for i in range(1, 5):
    if X[i] != F[st + i]:
        print(i)
        exit()
print(5)