#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int n, i, sum = 0, mx, ans;
  long long int a[100005];
  cin >> n;
  for (i = 0; i < n; i++) {
    cin >> a[i];
    sum = sum + a[i];
  }
  mx = *max_element(a, a + n);
  sum = sum - mx;
  ans = mx - sum;
  ans++;
  cout << ans;
  return 0;
}
