#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  vector<int> v(n);
  for (int i = 0; i < n; ++i) cin >> v[i];
  sort(v.begin(), v.end());
  long long s = 0;
  for (int i = 0; i < n - 1; ++i) s += v[i];
  cout << max(1LL, v[n - 1] + 1 - s);
}
