#include <bits/stdc++.h>
using namespace std;
int main() {
  int x;
  cin >> x;
  vector<int> a(x);
  for (int i = 0; i < x; i++) cin >> a[i];
  sort(a.rbegin(), a.rend());
  int big = a[0], others = 0;
  for (int i = 1; i < x; i++) others += a[i];
  cout << big - others + 1;
}
