#include <bits/stdc++.h>
using namespace std;
int ar[123456];
int n;
int main() {
  cin >> n;
  int sum = 0, maxi = -1;
  for (int i = 0; i < n; i++) {
    cin >> ar[i];
    sum += ar[i];
    maxi = max(maxi, ar[i]);
  }
  cout << abs(2 * maxi - sum) + 1 << endl;
  return 0;
}
