#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;
using ll = long long;


const ll mod = 1000000007;
int main(){
    vector<ll> a(5);
    for(int i = 0; i < 5; i++){
        cin >> a[i];
    }
    reverse(a.begin() , a.end());
    vector<ll> fib(1000);
    fib[0] = 1;
    fib[1] = 1;
    for(int i = 2; i < 1000; i++){
        fib[i] = fib[i - 1] + fib[i - 2];
        //fib[i] %= mod;
    }
    int ans = 0;
    for(int i = 0; i < 1000; i++){
        if(fib[i] == a[0]){
            int now = 1;
            for(int j = 1; j < 5; j++){
                if(fib[i + j] == a[j])now++;
                else break;
            }
            ans = max(ans , now);
        }
    }
    cout << ans << endl;
    return 0;
}