TOI10: Prime

#include <iostream>
#include <vector>
using namespace std;

#define lli long long
const int N = 10000000;
bool prime[N];

int main(){

    int n;
    scanf("%d", &n);
    int cnt = 0;
    for(int i = 2; i < N; ++i){
        if(!prime[i]){
            ++cnt;
            if(cnt == n){
                cout << i;
                break;
            }
            for(int j = i; j < N; j += i){
                prime[j] = true;
            }
        }
    }

    return 0;
}