#include <bits/stdc++.h>
using namespace std;
long arr[100005];
int main() {
  int n;
  cin >> n;
  long sum = 0;
  for (int i = 0; i < n; i++) {
    cin >> arr[i];
    sum += arr[i];
  }
  sort(arr, arr + n, greater<long>());
  for (int i = 0; i < n; i++) {
    if (2 * arr[i] >= sum) {
      cout << 2 * arr[i] - sum + 1;
      break;
    }
  }
}
