#include <bits/stdc++.h>   using namespace std;   int main() {     int n;     cin >> n;     int arr[n];     for (int i = 1; i <= n; i++) cin >> arr[i];     int ans = 0, ct0 = 0, ct1;     for (int i = 1; i <= n; i++) {       if (arr[i] == 1) {         ct1 = 0;         for (int j = i; j <= n; j++) {           if (arr[j] == 1) {             ct1 += 1;           }         }         ans = max(ans, ct0 + ct1);       } else {         ct0 += 1;         ans = max(ans, ct0);       }     }     cout << ans << endl;   }   