#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:167177216")
using namespace std;
const int MAX = 2147483647;
const int MAXN = 201000;
const long long MOD = 1000000000 + 7;
int main() {
  int n;
  cin >> n;
  vector<int> l(n);
  for (int i = 0; i < n; ++i) {
    cin >> l[i];
  }
  sort((l).begin(), (l).end());
  int sum = 0;
  for (int i = 0; i < n - 1; ++i) sum += l[i];
  int ans = l[n - 1] - sum + 1;
  cout << ans;
  return 0;
}
