FJ and his cows enjoy playing a mental game. They write down the numbers from 1 to $N$ $(1 \le N \le 10)$ in a certain order and then sum adjacent numbers to produce a new list with one fewer number. They repeat this until only a single number is left. For example, one instance of the game (when $N=4$) might go like this:
3 1 2 4
4 3 6
7 9
16Behind FJ's back, the cows have started playing a more difficult game, in which they try to determine the starting sequence from only the final total and the number $N$. Unfortunately, the game is a bit above FJ's mental arithmetic capabilities.
Write a program to help FJ play the game and keep up with the cows.
Input
- Line 1: Two space-separated integers: $N$ and the final sum.
Output
- Line 1: An ordering of the integers 1..$N$ that leads to the given sum. If there are multiple solutions, choose the lexicographically least, i.e. the one that puts smaller numbers first.
Examples
Input 1
4 16
Output 1
3 1 2 4
There are other possible sequences, such as 3 2 1 4, but 3 1 2 4 is lexicographically smallest.
Problem by Harry Wiggins (2002).