#include <bits/stdc++.h>
using namespace std;
int main() {
  std::ios_base::sync_with_stdio(false);
  int n;
  cin >> n;
  vector<long long> v;
  long long side;
  for (int i = 0; i < n; i++) {
    cin >> side;
    v.push_back(side);
  }
  sort(v.begin(), v.end());
  long long sum = 0;
  for (int i = 0; i < n - 1; i++) {
    sum += v[i];
  }
  int big = max(sum, v[n - 1]);
  int small = min(sum, v[n - 1]);
  cout << big - small + 1 << endl;
}
