#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 6;
int len[N];
int main() {
  int n;
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%d", &len[i]);
  }
  sort(len + 1, len + n + 1);
  long long sum = 0;
  for (int i = 1; i < n; i++) {
    sum += (long long)len[i];
  }
  cout << len[n] - sum + 1 << "\n";
  return 0;
}
