fib = [1]
data = 1
while data <= 10 ** 15:
    fib.append(data)
    data = fib[-2] + fib[-1]
    
A = [int(input()) for i in range(5)][::-1]

ans = 0

for i in range(len(fib)):
    for j in range(5):
        if i + j >= len(fib):
            break
        if fib[i + j] == A[j]:
            ans = max(ans, j + 1)
        else:
            break
print(ans)