#include <bits/stdc++.h>
using namespace std;
const int N = 100050;
int l[N], n;
long long ave;
int main() {
  int i;
  scanf("%d", &n);
  for (i = 1; i <= n; ++i) scanf("%d", &l[i]);
  sort(l + 1, l + n + 1);
  for (i = 1; i < n; ++i) ave += l[i];
  cout << l[n] - ave + 1 << endl;
  return 0;
}
