#include <bits/stdc++.h>
using namespace std;
const int M = 1000000007;
int main() {
  long long n, i;
  cin >> n;
  long long s = 0, t, ma = 0;
  for (i = 0; i < n; i++) {
    cin >> t;
    s += t;
    ma = max(ma, t);
  }
  s = 2 * ma - s + 1;
  cout << s << endl;
}
