#include <bits/stdc++.h>
using namespace std;
const long long INF = 1e18, MAXN = 1e5 + 100;
long long n, a[MAXN], s;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cin >> n;
  for (long long i = 0; i < n; i++) cin >> a[i];
  sort(a, a + n);
  for (long long i = 0; i < n - 1; i++) s += a[i];
  cout << a[n - 1] - s + 1 << endl;
}
