#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define all(x) (x).begin(), (x).end()
#define ll long long
#define ld long double
#define INF 1000000000000000000
typedef pair<ll, ll> pll;
typedef pair<int, int> pint;

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    int N;
    cin >> N;
    int MAX = pow(10, 6);
    vector<int> is_prime(MAX, 1);
    is_prime[0] = 0, is_prime[1] = 0;
    for (int i = 2; i < MAX; ++i) {
        if (!is_prime[i])
            continue;
        for (int j = 2 * i; j < MAX; j += i)
            is_prime[j] = 0;
    }

    if (N == 1) {
        cout << 1 << endl;
    } else {
        N -= 1;
        int cnt = 0;
        for (int i = pow(10, 5) + 1; i < MAX; i++) {
            if (is_prime[i])
                cnt++;
            if (cnt == N) {
                cout << i << endl;
                return 0;
            }
        }
    }
}