#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)(n);i++)
using namespace std;
using ll = long long ;
using P = pair<int,int> ;
using pll = pair<long long,long long>;
constexpr int INF = 1e9;
constexpr long long LINF = 1e17;
constexpr int MOD = 1000000007;

bool prime(int i){
    for(int j=2;j*j<=i;j++){
        if(i%j==0) return false;
    }
    return true;
}

int main(){
    int n;
    cin >> n;
    if(n==1){
        cout << 1 << endl;
        return 0;
    }
    int cnt = 1;
    int now = 100001;
    while(1){
        if(prime(now)){
            ++ cnt;
            if(cnt == n){
                cout << now << endl;
                break;
            }
        }
        ++ now;
    }
    return 0;
}