#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  long long sm = 0, mx = 0;
  vector<long long> v(n, 0);
  for (int i = 0; i < n; i++) {
    cin >> v[i];
    sm += v[i];
    mx = max(mx, v[i]);
  }
  long long res = mx - sm + mx;
  cout << res + 1 << endl;
  return 0;
}
