#include <bits/stdc++.h>
using namespace std;

const int N = 1000000;

char a[N], b[N];

int equiv(string a, string b) {
  if (a == b) return 1;
  if (a.length()%2) return 0;
  int len = a.length();
  string a1 = a.substr(0, len/2);
  string a2 = a.substr(len/2,len/2);
  string b1 = b.substr(0, len/2);
  string b2 = b.substr(len/2,len/2);
  return (equiv(a1, b2) and equiv(a2, b1)) or (equiv(a1, b1) and equiv(a2, b2));
}

int main() {
  scanf("%s %s", a, b);
  printf("%s\n", equiv(a, b)?"YES":"NO");
  return 0;
}