A permutation p is an ordered group of numbers p 1, p 2, ..., p n , consisting of n distinct positive integers, each is no more than n . We'll define number n as the length of permutation p 1, p 2, ..., p n . Simon has a positive integer n and a non-negative integer k , such that 2k ≤ n . Help him find permutation a of length 2n , such that it meets this equation: .

输入描述:

The first line contains two integers n and k (1 ≤ n ≤ 50000, 0 ≤ 2k ≤ n).

输出描述:

Print 2n integers a1, a2, ..., a2n — the required permutation a. It is guaranteed that the solution exists. If there are multiple solutions, you can print any of them.

备注:

Record x represents the absolute value of number x. In the first sample 1 - 2 - 1 - 2 = 0.In the second sample 3 - 2 + 1 - 4 - 3 - 2 + 1 - 4 = 1 + 3 - 2 = 2.In the third sample 2 - 7 + 4 - 6 + 1 - 3 + 5 - 8 - 2 - 7 + 4 - 6 + 1 - 3 + 5 - 8 = 12 - 12 = 0.