#include <bits/stdc++.h>

using namespace std;

int main(void) {
  int n;
  cin >> n;

  int v[1010];
  for (int i = 0; i < n; i++) {
    cin >> v[i];
  }

  int dp[1010] = {};
  for (int i = 0; i < n; i++) {
    dp[i] = v[i];
    for (int j = 0; j < i - 1; j++) {
      dp[i] = max(dp[i], dp[j] + v[i]);
    }
  }
  
  int ans = 0;
  for (int i = 0; i < n; i++) {
    ans = max(ans, dp[i]);
  }
  cout << ans << endl;

  return 0;
}