可云谁来救我表情包:有段英文程序帮忙翻译

ACM浙大在线答题,可我连题目都看不懂!谢谢你们帮我翻译下!
忘了写英文了:
A traveller plans a round trip through n cities, where n is a power of 2, in
which case we simply index them with numeric values from 0 to n - 1. The
traveller lives in one of them, and that's where he will start and end his trip.
He only visits each city once, and for some particular reason the two adjacent
cities on his trip should satify an equation that (A xor B) is also a power of 2.
For his odd mind no travel agency is willing to offer any help and finally he
comes to you for a solution. You would either tell him it's not possible to
arrange a trip for him.
Input
Input has two integers n and m, which are respectively the number of cities and
the city he lives in.
Proceed through multiple cases until you meet a case n = 0.
Output
Print "NO" or a list of n city numbers on a single line separated by a single
space.
Sample Input
2 1
4 0
0 0
Sample Output
1 0
0 1 3 2