#include <bits/stdc++.h>
using namespace std;
int main() {
  int a[3100];
  int n;
  cin >> n;
  for (int i = 1; i <= n; i++) {
    scanf("%d", &a[i]);
  }
  sort(a + 1, a + n + 1);
  for (int i = 1; i <= n; i++)
    if (i != a[i]) {
      cout << i << endl;
      return 0;
    }
  cout << n + 1;
  return 0;
}
