import java.util.Scanner;

/*
 *  Sieve of Eratosthenes
 *  A quick method to calculate prime numbers.
 *
 * @author Divyanshu Sharma
 */

public class fast_prime {

   public static void main(String[] args) {
       
    Scanner in = new Scanner(System.in);
    System.out.println("Enter the number: ");
    int num = in.nextInt();
    fast_prime get = new fast_prime();
    get.no_of_Prime(num);
    in.close();
    }

   void no_of_Prime(int num) {
        boolean[] pri = new boolean[num+1];
        
        for(int i=2; i