#include <bits/stdc++.h>
using namespace std;

int main(){
    vector<long long> fib(75), a(5);
    for(auto &&v:a)cin >> v;
    reverse(a.begin(), a.end());
    fib[0] = fib[1] = 1;
    for(int i = 2; i < 75; i++)fib[i] = fib[i - 1] + fib[i - 2];
    int st = lower_bound(fib.begin(), fib.end(), a[0]) - fib.begin();
    if(st == 0 && a[1] == 2)st++;
    for(int i = 0; i < 5; i++){
        if(a[i] != fib[st + i]){
            cout << i << '\n';
            return 0;
        }
    }
    cout << 5 << '\n';
}