import java.util.Scanner;

public class yuki495 {
    
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();

        int a = 0;
        int b = 0;
        int c = 0;

        a = N/100;
        N = N%100;
        b = N/10;
        N = N%10;
        c = N;

        if(a+c==b){
            System.out.println("yes");
        }else{
            System.out.println("no");
        }

        sc.close();


        
    }

}