import java.util.Scanner;

public class Main {

public static void main(String[] args) {
	int ji=0;
	int number1=0;
	Scanner sss=new Scanner(System.in);
	int q=sss.nextInt();
	for(int i=2;i<=q;i++) {
		int number=0;
			if(i%i==0&&i%1==0) {
				for(int ii=1;ii<i;ii++) {
					if(i%ii==0&&ii!=1){
						number++;
					}if(number==0&&ii==i-1) {
						ji+=i;
						if(ji<=q) {
							number1++;
							System.out.println(i);
						}			
					}
				}
			}
	}
	System.out.println(number1);
	sss.close();
}

}