#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); i++)
using namespace std;
typedef long long ll;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    
    vector<ll> a(5);
    rep(i,5) cin >> a[i];
    reverse(a.begin(), a.end());

    vector<ll> f(80, 0);
    f[0] = 1; f[1] = 1;
    for(int i = 2; i < 80; i++) f[i] = f[i - 1] + f[i - 2];

    int n = 0;
    for(int i = 0; i < 80; i++) {
        int cur = 0;
        for(int j = 0; j < 5; j++) {
            if(a[j] == f[i + j]) {
                cur++;
            } else {
                break;
            }
        }
        n = max(n, cur);
    }
    cout << n << endl;
}