typedef long long ll;
#include <iostream>
#include <vector>
#include <stdio.h>
using namespace std;

bool isPrime(ll x){
    if (x % 2 == 0) return x == 2;
    ll d = 3;
    while (d * d <= x){
        if (x % d == 0) return false;
        d += 2;
    }
    return true;
}

int main(){
    //freopen("test.txt", "w", stdout);
    ll k;
    cin >> k;
    vector<ll> primes;

    for(int i = 2; i < 45000; i++)
        if (isPrime(i))
            primes.push_back(i);

    ll n_const = 90000042;

    vector<bool> a(n_const, true);

    for (ll prime = 0; prime < primes.size(); prime++)
        for (ll i = primes[prime] * primes[prime]; i < n_const; i += primes[prime])
            a[i] = 0;

    //cout << "[2";
    ll ans = 1;
    for(ll i = 2; i < n_const; i++)
        if (a[i]){
            if (ans == k){
                cout << i;
                return 0;
            }
            ans += 1;
        }
    //cout << "]";

    return 0;
}