#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  long long l[n];
  for (int i = 0; i < n; i++) cin >> l[i];
  sort(l, l + n);
  reverse(l, l + n);
  vector<long long> a(3, 0);
  int x = 0, prev = 2;
  for (int i = 0; i < n;) {
    a[x] += l[i];
    int j = i + 1;
    while (a[x] < a[prev] && j < n) a[x] += l[j], j++;
    prev = x;
    x = (x + 1) % 3;
    i = j;
  }
  if (a[0] + a[1] <= a[2])
    cout << a[2] - a[0] - a[1] + 1;
  else if (a[1] + a[2] <= a[0])
    cout << a[0] - a[2] - a[1] + 1;
  else if (a[0] + a[2] <= a[1])
    cout << a[1] - a[2] - a[0] + 1;
}
