#include <bits/stdc++.h>
using namespace std;
int n;
long long a[100001];
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; ++i) scanf("%lld", a + i);
  sort(a, a + n);
  long long sum = 0;
  for (int i = 0; i < n - 1; ++i) sum += a[i];
  printf("%lld\n", a[n - 1] + 1 - sum);
  return 0;
}
