import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc = new Scanner(System.in);
		int a = sc.nextInt();
		if(a>1 && a<100){
			System.out.println("yes");
		}else{
			System.out.println();
		}
		sc.close();
	}

}
/**************************************************************
	Problem: 1641
	User: admin
	Language: Java
	Result: Accepted
	Time:755 ms
	Memory:39716 kb
****************************************************************/