#include <bits/stdc++.h>
using namespace std;
const int maxn = (int)2e5 + 10;
const int mod = (int)1e9 + 7;
const int inf = (1 << 30) - 1;
int n, m;
int a[maxn];
int b[maxn];
void solve() {
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
  }
  cout << 2 * (*max_element(a, a + n)) - accumulate(a, a + n, 0) + 1 << "\n";
}
int main() {
  int t = 1;
  for (int i = 1; i <= t; i++) {
    solve();
  }
  return 0;
}
