#include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < (n); i ++)
using namespace std;
typedef long long ll;
typedef pair<ll,ll> PL;
typedef pair<int,int> P;
const int INF = 1e9;
const ll MOD = 1e9 + 7;

bool judge(int x){
    for (int i = 2;i <= 100000;i++){
        if (x%i == 0)return false;
    }
    for (int i = 2;i*i <= x;i++){
        if (x&i == 0)return false;
    }
    return true;
}

int main() {
    int N; cin >> N;
    if (N == 1){
        cout << 1 << endl;
        return 0;
    }
    int x = 100000;
    while (1){
        x ++;
        if (judge(x)){
            N --;
            if (N == 1) break;
        }
    }
    cout << x << endl;
}