#include <bits/stdc++.h>
using namespace std;
const long double pi = 4 * atan((long double)1);
const long long mod = 1e9 + 7;
const long long inf = 1e9;
const long long llinf = 1e18;
const long long nax = 0;
long long n;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  cin >> n;
  vector<long long> arr(n + 5);
  long long maks = 0, sums = 0;
  for (int i = 0; i < n; ++i) {
    cin >> arr[i];
    sums += arr[i];
    maks = max(maks, arr[i]);
  }
  long long butuh = maks - (sums - maks);
  cout << butuh + 1 << '\n';
}
