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