output_description: If it is impossible to partition the integers satisfying the condition, print
  `-1`. If it is possible, print N triples in the following format:
  
      
      
      a_1 b_1 c_1
      :
      a_N b_N c_N
      
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N K
attempt: import sys
  
  read = sys.stdin.buffer.read
  readline = sys.stdin.buffer.readline
  readlines = sys.stdin.buffer.readlines
  
  import numpy as np
  
  N, K = map(int, read().split())
  
  
  def solve_even(N, K):
      L = N // 2
      x = np.arange(K, K + N)
      y = np.concatenate(
          [np.arange(K + L + N, K + L + N + L), np.arange(K + N, K + L + N)]
      )
      add = N - (K + L)
      z = x + y + add
      z[L:] += 1
      answer = np.vstack([x, y, z]).T
      print("\n".join(" ".join(row) for row in answer.astype(str)))
  
  
  def solve_odd(N, K):
      L = N // 2
      x = np.arange(K, K + N)
      y = np.concatenate(
          [np.arange(K + L + N, K + L + N + L + 1), np.arange(K + N, K + L + N)]
      )
      add = N - (K + L)
      z = x + y + add
      answer = np.vstack([x, y, z]).T
      print("\n".join(" ".join(row) for row in answer.astype(str)))
  
  
  def solve(N, K):
      if K + K > N + 1:
          print(-1)
          return
      if N & 1:
          solve_odd(N, K)
      else:
          solve_even(N, K)
  
  
  solve(N, K)
  
problem_description: Statement
  
  Given are positive integers N and K.
  
  Determine if the 3N integers K, K+1, ..., K+3N-1 can be partitioned into N
  triples (a_1,b_1,c_1), ..., (a_N,b_N,c_N) so that the condition below is
  satisfied. Any of the integers K, K+1, ..., K+3N-1 must appear in exactly one
  of those triples.
  
    * For every integer i from 1 to N, a_i + b_i \leq c_i holds.
  
  If the answer is yes, construct one such partition.
samples: [{"input": "1 1", "output": "1 2 3\n    \n\n* * *"}, {"input": "3 3", "output": "-1"}]