#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  int a[n], x = 0;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    if (a[i] == 1) {
      x++;
    }
  }
  if (x == n) {
    cout << n - 1 << "\n";
  } else {
    int p = 0, m = 0;
    for (int i = 0; i < n; i++) {
      m = 0;
      for (int j = i; j < n; j++) {
        if (a[j] == 0) {
          m++;
        } else {
          m--;
        }
        p = max(m, p);
      }
    }
    cout << x + p << "\n";
  }
}
