#include <bits/stdc++.h>
using namespace std;
bool isNonDegenerateTriangle(int a, int b, int c) {
  return (a + b > c && b + c > a && c + a > b);
}
bool isDegenerateTriangle(int a, int b, int c) {
  return (a + b == c || b + c == a || c + a == b);
}
int main() {
  int n;
  cin >> n;
  long long int a[n], s = 0;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    s += a[i];
  }
  sort(a, a + n);
  cout << 2 * a[n - 1] - s + 1;
}
