#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int n, num, max = 0, diff, sum = 0;
  cin >> n;
  for (long long int i = 0; i < n; ++i) {
    cin >> num;
    sum += num;
    if (num > max) {
      max = num;
    }
  }
  diff = sum - max;
  diff = max - diff;
  cout << diff + 1 << endl;
  return 0;
}
