import java.util.Scanner;
public class test {
  public static void main(String args[]) {
    Scanner in = new Scanner(System.in);
    long i,tof;
    int n,j,ii;
    boolean test;
    long a[];
    n = in.nextInt();
    a = new long[n];
    a[0] = 2;
    ii = 1;
    for(i = 3; ii < n; i+=2) {
      tof = Math.round(Math.sqrt(i) - 0.5);
      test = true;
      for(j = 0; a[j] <= tof; j++)
        if (i % a[j] == 0)
          test = false;
      if (test) {
        a[ii] = i;
        ii++;
      }
    }
    System.out.println(a[a.length - 1]);
  }
}