#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(0);
  int n;
  long long mmax = 0;
  long long sum = 0;
  long long num;
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> num;
    sum += num;
    mmax = max(mmax, num);
  }
  cout << 2 * mmax - sum + 1 << endl;
}
