x = y = 1
fib = []
while x < 10**15:
    fib.append(x)
    x,y = y,x+y
L = len(fib)
a = [int(input()) for _ in range(5)][::-1]
ans = 0
for i in range(1):
    for j in range(i+1,6):
        for k in range(L-j+i):
            if a[i:j] == fib[k:k+j-i]:
                ans = max(ans,j-i)
print(ans)