#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main(){
    vector<long long> a(5);
    for(int i = 0; 5 > i; i++){
        cin>>a[i];
    }
    reverse(a.begin(),a.end());
    int A = 1;
    int B = 1;
    while(a[0] > A){
        A = A+B;
        swap(A,B);
    }
    int ans = 0;
    while(ans != 5 && a[ans] == A){
        ans++;
        A = A+B;
        swap(A,B);
    }
    cout << ans << endl;
    
}