#include <bits/stdc++.h>
using namespace std;
int arr[1000000];
int n;
int main() {
  cin >> n;
  int maxi = 0, sum = 0;
  for (int i = 1; i <= n; i++) {
    cin >> arr[i];
    sum += arr[i];
    maxi = max(maxi, arr[i]);
  }
  cout << maxi - sum + maxi + 1;
  return 0;
}
