first_str = str(input())
target_str = str(input())

def discriminator(s1,s2):
    counter=0
    for e1,e2 in zip(s1,s2):
        if not e1==e2:
            counter+=1
            
    if (counter%2==0) or (counter==0):
        return 'YES'
    else:
        return 'NO'
        
print(discriminator(first_str, target_str))