#include <bits/stdc++.h>
using namespace std;
long long n, ans, med;
vector<long long> vc;
int main() {
  cin >> n;
  for (long long i = 0; i < n; i++) {
    cin >> med;
    vc.push_back(med);
  }
  sort(vc.begin(), vc.end());
  for (long long i = 0; i < n - 1; i++) {
    ans += vc[i];
  }
  if (vc[n - 1] <= ans)
    puts("1");
  else
    cout << (vc[n - 1] - ans) + 1 << endl;
  return 0;
}
