Problem:
Score : 800 points

Problem Statement

You are given integers N,\ A and B.
Determine if there exists a permutation (P_0,\ P_1,\ ...\ P_{2^N-1}) of (0,\ 1,\ ...\ 2^N-1) that satisfies all of the following conditions, and create one such permutation if it exists.

P_0=A

P_{2^N-1}=B

For all 0 \leq i < 2^N-1, the binary representations of P_i and P_{i+1} differ by exactly one bit.

Constraints

1 \leq N \leq 17

0 \leq A \leq 2^N-1

0 \leq B \leq 2^N-1

A \neq B

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N A B

Output

If there is no permutation that satisfies the conditions, print NO.

If there is such a permutation, print YES in the first line.
Then, print (P_0,\ P_1,\ ...\ P_{2^N-1}) in the second line, with spaces in between.
If there are multiple solutions, any of them is accepted.

Sample Input 1

2 1 3

Sample Output 1

YES
1 0 2 3

The binary representation of P=(1,0,2,3) is (01,00,10,11), where any two adjacent elements differ by exactly one bit.

Sample Input 2

3 2 1

Sample Output 2

NO

Solution in PyPy2 (5.6.0) (judge verdict: Wrong Answer)

#!/usr/bin/env python2
"""
This file is part of https://github.com/cheran-senthil/PyRival
Copyright 2019 Cheran Senthilkumar <hello@cheran.io>

"""
from __future__ import division, print_function

import itertools
import os
import sys
from atexit import register
from cStringIO import StringIO

range = xrange

filter = itertools.ifilter
map = itertools.imap
zip = itertools.izip

sys.stdout = StringIO()
register(lambda: os.write(1, sys.stdout.getvalue()))
input = StringIO(os.read(0, os.fstat(0).st_size)).readline


def s_permutations(seq):
    items = [[]]
    for j in seq:
        new_items = []
        for i, item in enumerate(items):
            if i % 2:
                # step up
                new_items += [item[:i] + [j] + item[i:] for i in range(len(item) + 1)]
            else:
                # step down
                new_items += [item[:i] + [j] + item[i:] for i in range(len(item), -1, -1)]
        items = new_items

    return items


def main():
    n, a, b = map(int, input().split())

    k = a ^ b
    if k & (k - 1) == 0:
        for item in s_permutations(range(1 << n)):
            if item[0] == a and item[-1] == b:
                print('YES')
                print(*item)
                return
        print('NO')
    else:
        print('NO')


if __name__ == '__main__':
    main()