#include<bits/stdc++.h> using namespace std; int a[10001]; int main(){ int n; cin >> n; for(int i = 1; i <= n; i++){ cin >> a[i]; } int sum = a[0] + a[1] + a[2]; for(int i = 1; i <= n - 2; i++){ sum = max(sum, a[i] + a[i + 1] + a[i + 2]); } cout << sum; return 0; }