using System;

public class Program

{

    public static void Main()

    {

    int n1=int.Parse(Console.ReadLine());

    int n2=int.Parse(Console.ReadLine());   

    if(check(n1,n2))

    Console.WriteLine("yes");

    else

    Console.WriteLine("no");    

​

    }   

    public static bool check(int n1,int n2)

    {

    bool ok=true;   

    int c=0,d=0;    

    while(n1!=0)

    {

    c++;        

    n1/=10;

    }

    while(n2!=0)

    {

    d++;        

    n2/=10;

    }

    if(!(c%2==0&&d%2==0))

    ok=false;   

    while(n1!=0)

    {

    if(!(n1%100+1==n2%100))

    ok=false;

    n1/=100;

    n2/=100;    

    }

    if(ok)

    return true;

    else

    return false;   

    }   

​

​

}