#include <bits/stdc++.h>
using namespace std;
using lint = long long int;
template<typename T> istream &operator>>(istream &is, vector<T> &vec){ for (auto &v : vec) is >> v; return is; }


int main()
{
    vector<lint> A(5);
    cin >> A;
    reverse(A.begin(), A.end());
    A.push_back(-1);

    lint n = 1, prv = 0;
    if (A[0] == 1 and A[1] == 2) prv = 1;

    while (n < A[0]) {
        prv += n;
        swap(n, prv);
    }
    int t = 0;
    while (A[t] == n) {
        t++;
        prv += n;
        swap(n, prv);
    }
    cout << t << endl;
}