#include <cstdio>
#include <string>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <list>
#include <iterator>
#include <cassert>
#include <numeric>
#include <functional>
//#include <numeric>
#pragma warning(disable:4996) 
 
typedef long long ll;
typedef unsigned long long ull;
#define MIN(a, b) ((a)>(b)? (b): (a))
#define MAX(a, b) ((a)<(b)? (b): (a))
#define LINF  9223300000000000000
#define LINF2 1223300000000000000
#define INF 2140000000
const long long MOD = 1000000007;
//const long long MOD = 998244353;

using namespace std;

vector<int> pp;
void preparePrime( int maxp )
{
    int i;
    vector<int> a(maxp+1);
    for(i=2; i<=maxp; i++) {
        int k=i+i;
        while(k<=maxp) {
            a[k]=1;
            k+=i;
        }
    }
    for(i=2; i<=maxp; i++) {
        if(a[i]==0) pp.push_back( i );
    }
    return;
}

void solve()
{
    int n;
    scanf("%d", &n);
    if (n == 1) {
        printf("1\n"); return;
    }
    
    preparePrime(100100);
    vector<int> flag(100500);
    int i;
    for (i=0; i<(int)pp.size(); i++) {
        flag[pp[i]] = 1;
    }
    int cnt = 1;
    for (i = 100001; i < 100500; i++) {
        if (flag[i] == 0) {
            cnt++;
            if (cnt == n) {
                printf("%d\n", i);
                return;
            }
        }
    }

    return;
}


int main(int argc, char* argv[])
{
#if 1
    solve();
#else
    int T;
    scanf("%d", &T);
    int t;
    for(t=0; t<T; t++) {
        //printf("Case #%d: ", t+1);
        solve();
    }
#endif
    return 0;
}