output_description: Print the minimum possible value of h_{max} - h_{min}.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N K
      h_1
      h_2
      :
      h_N
attempt: n,k=map(int,input().split())
  hList=[]
  for i in range(n):
    hList.append(int(input()))
  hList.sort()
  //print(hList)
  ans=100000000000000
  for i in range(n-k+1):
    tmp=hList[i+k-1]-hList[i]
    if(ans>tmp):
      ans=tmp
  print(ans)
problem_description: Statement
  
  In some other world, today is Christmas Eve.
  
  There are N trees planted in Mr. Takaha's garden. The height of the i-th tree
  (1 \leq i \leq N) is h_i meters.
  
  He decides to choose K trees from these trees and decorate them with electric
  lights. To make the scenery more beautiful, the heights of the decorated trees
  should be as close to each other as possible.
  
  More specifically, let the height of the tallest decorated tree be h_{max}
  meters, and the height of the shortest decorated tree be h_{min} meters. The
  smaller the value h_{max} - h_{min} is, the better. What is the minimum
  possible value of h_{max} - h_{min}?
samples: [{"input": "5 3\n    10\n    15\n    11\n    14\n    12", "output": "2\n    \n\nIf we decorate the first, third and fifth trees, h_{max} = 12, h_{min} = 10 so\nh_{max} - h_{min} = 2. This is optimal.\n\n* * *"}, {"input": "5 3\n    5\n    7\n    5\n    7\n    7", "output": "0\n    \n\nIf we decorate the second, fourth and fifth trees, h_{max} = 7, h_{min} = 7 so\nh_{max} - h_{min} = 0. This is optimal.\n\nThere are not too many trees in these sample inputs, but note that there can\nbe at most one hundred thousand trees (we just can't put a sample with a\nhundred thousand lines here)."}]