#include <bits/stdc++.h>   using namespace std;   int main() {     int n, s = 1, i;     cin >> n;     int a[n];     for (i = 0; i < n; i++) {       cin >> a[i];       if (a[i] == s) {         s++;       }     }     cout << s - 1 << endl;     s = 1;     for (i = 0; i < n; i++) {       if (a[i] == s) {         cout << i + 2001 <<    ;         s++;       }     }   }   