output_description: Print the minimum time required to light K candles.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N K
      x_1 x_2 ... x_N
attempt: import itertools
  import collections
  n,k=map(int,input().split())
  candle=list(map(int,input().split()))
  com=list(itertools.product([1,0], repeat=n))
  ans=200000000
  for i in range(2**n):
    count=collections.Counter(com[i])
    if count[1]==k:
      begin=0
      end=0
      cnt=0
      temp=0
      print(
      for j in range(n):
        if com[i][j]==1:
          cnt+=1
          if cnt==1:
            start=candle[j]
          elif cnt==k:
            end=candle[j]
            break;
      if start>=0:
        temp=abs(end)
        if temp<ans:
          ans=temp
      if end<=0:
        temp=abs(start)
        if temp<ans:
          ans=temp
      else:
        temp=min(abs(start), end)*2+max(abs(start), end)
        if temp<ans:
          ans=temp
  print(ans)
problem_description: Statement
  
  There are N candles placed on a number line. The i-th candle from the left is
  placed on coordinate x_i. Here, x_1 < x_2 < ... < x_N holds.
  
  Initially, no candles are burning. Snuke decides to light K of the N candles.
  
  Now, he is at coordinate 0. He can move left and right along the line with
  speed 1. He can also light a candle when he is at the same position as the
  candle, in negligible time.
  
  Find the minimum time required to light K candles.
samples: [{"input": "5 3\n    -30 -10 10 20 50", "output": "40\n    \n\nHe should move and light candles as follows:\n\n  * Move from coordinate 0 to -10.\n  * Light the second candle from the left.\n  * Move from coordinate -10 to 10.\n  * Light the third candle from the left.\n  * Move from coordinate 10 to 20.\n  * Light the fourth candle from the left.\n\n* * *"}, {"input": "3 2\n    10 20 30", "output": "20\n    \n\n* * *"}, {"input": "1 1\n    0", "output": "0\n    \n\n  * There may be a candle placed at coordinate 0.\n\n* * *"}, {"input": "8 5\n    -9 -7 -4 -3 1 2 3 4", "output": "10"}]