Time Limit: 1 second
Memory Limit: 256 megabytes
Permutation p is an ordered set of integers p1, p2, ..., pn, consisting of n distinct positive integers not larger than n. We'll denote as n the length of permutation p1, p2, ..., pn.
Your task is to find such permutation p of length n, that the group of numbers |p1 - p2|, |p2 - p3|, ..., |pn - 1 - pn| has exactly k distinct elements.
The single line of the input contains two space-separated positive integers n, k (1 ≤ k < n ≤ 105).