a = [int(input()) for _ in range(5)]
a = a[::-1]
dp = [0]*100
dp[0] = 1
dp[1] = 1

for i in range(2, 100):
    dp[i] = dp[i-1]+dp[i-2]
    
ans = 0

for i in range(100):
    if dp[i]==a[0]:
        c = 1
        
        while c<5 and dp[i+c]==a[c]:
            c += 1
        
        ans = max(ans, c)

print(ans)