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 2 k ≤ n . Help him find permutation a of length 2 n , such that it meets this equation: . The first line contains two integers n and k ( 1 ≤ n ≤ 50000 , 0 ≤ 2 k ≤ n ). Print 2 n integers a 1 , a 2 , ..., a 2 n — the required permutation a . It is guaranteed that the solution exists. If there are multiple solutions, you can print any of them. 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 .