#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  long long ar[n], s = 0;
  for (int i = 0; i < n; i++) cin >> ar[i];
  sort(ar, ar + n);
  for (int i = 0; i < n - 1; i++) s += ar[i];
  cout << ar[n - 1] - s + 1;
  return 0;
}
