#include <bits/stdc++.h>   using namespace std;   int n, maxi = 2, ans = 2;   int a[100005];   vector<int> num;   int main() {     cin >> n;     for (int i = 0; i < n; i++) cin >> a[i];     if (n < 3) {       cout << n;       return 0;     }     for (int i = 2; i < n; i++) {       if (a[i] == a[i - 1] + a[i - 2]) {         ans++;         maxi = max(maxi, ans);       } else         ans = 2;     }     cout << maxi;     return 0;   }   