#include <bits/stdc++.h>
using namespace std;
const int NAX = 1e6, MOD = 1e9 + 7, POW = 19;
const long double PI = 3.14159265358979;
int n, arr[1000000];
int main() {
  cin >> n;
  for (int i = 0; i < n; i++) cin >> arr[i];
  sort(arr, arr + n);
  long long sum = 0;
  for (int i = 0; i < n - 1; i++) sum += arr[i];
  cout << arr[n - 1] - sum + 1;
  return 0;
}
