#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define rep(i, n) for (int i = 0; i < (n); i++)
#define P pair<int, int>

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

int main() {
  int n;
  cin >> n;
  int cnt = 1;
  int ans = 1;
  int i = 100001;
  while (cnt < n) {
    if (isPrime(i)) {
      cnt++;
      ans = i;
    }
    i++;
  }
  cout << ans << endl;


}