// editor2
#include<stdio.h>
#include<string.h>
int main(){
    char a[20];
    char b[20];
    scanf("%s%s",a,b);
    int len1=("%d",strlen(a));
    int len2=("%d",strlen(b));
    if(len1==len2){
        printf("YES");
    }else if(len1!=len2){
        printf("NO");
    }else if(!isalpha(a)||!isalpha(b)){
        printf("Invalid input");
    
}