Today on a lecture about strings Gerald learned a new definition of string equivalency. Two strings *a* and *b* of equal length are called equivalent in one of the two cases: 
 1.  They are equal. 1.  If we split string *a* into two halves of the same size *a*<sub class="lower-index">1</sub> and *a*<sub class="lower-index">2</sub>, and string *b* into two halves of the same size *b*<sub class="lower-index">1</sub> and *b*<sub class="lower-index">2</sub>, then one of the following is correct: <ol> <li> *a*<sub class="lower-index">1</sub> is equivalent to *b*<sub class="lower-index">1</sub>, and *a*<sub class="lower-index">2</sub> is equivalent to *b*<sub class="lower-index">2</sub> 1.  *a*<sub class="lower-index">1</sub> is equivalent to *b*<sub class="lower-index">2</sub>, and *a*<sub class="lower-index">2</sub> is equivalent to *b*<sub class="lower-index">1</sub> 
As a home task, the teacher gave two strings to his students and asked to determine if they are equivalent.

Gerald has already completed this home task. Now it's your turn!
The first two lines of the input contain two strings given by the teacher. Each of them has the length from 1 to 200 000 and consists of lowercase English letters. The strings have the same length.
"""
B. Equivalent Strings
time limit per test2 seconds
memory limit per test256 megabytes
inputstandard input
outputstandard output
Today on a lecture about strings Gerald learned a new definition of string equivalency. Two strings a and b of equal
length are called equivalent in one of the two cases:
They are equal.
If we split string a into two halves of the same size a1 and a2, and string b into two halves of the same size b1
and b2, then one of the following is correct:
a1 is equivalent to b1, and a2 is equivalent to b2
a1 is equivalent to b2, and a2 is equivalent to b1
As a home task, the teacher gave two strings to his students and asked to determine if they are equivalent.
Gerald has already completed this home task. Now it's your turn!
Input
The first two lines of the input contain two strings given by the teacher. Each of them has the length
from 1 to 200 000 and consists of lowercase English letters. The strings have the same length.
Output
Print "YES" (without the quotes), if these two strings are equivalent, and "NO" (without the quotes) otherwise.
"""


def equivalent(s1, s2):
    if s1 == s2:
        return True
    elif len(s1) == 1:
        return False
    left = slice(0, len(s1) // 2, 1)
    right = slice(len(s1) // 2, len(s1), 1)
    return (equivalent(s1[left], s2[left]) and equivalent(s1[right], s2[right])) or \
           (equivalent(s1[left], s2[right]) and equivalent(s1[right], s2[left]))


if __name__ == '__main__':
    a = input('Enter String 1')
    b = input('Enter String 2')
    if equivalent(a, b):
        print('YES')
    else:
        print('NO')
