#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  int n;
  cin >> n;
  int longest = 0, sum = 0;
  for (int i = 0; i < n; ++i) {
    int l;
    cin >> l;
    longest = max(longest, l);
    sum += l;
  }
  cout << longest - (sum - longest) + 1;
}
