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 sys
  import math  # noqa
  import bisect  # noqa
  import queue  # noqa
  
  
  def input():
      return sys.stdin.readline().rstrip()
  
  
  def solve(X, K):
      N = len(X)
  
      cumsum = [0 for _ in range(N)]
      for i in range(1, N):
          cumsum[i] = abs(X[i] - X[i - 1]) + cumsum[i - 1]
  
      idx_zero = bisect.bisect_left(X, 0)
  
      ret = 1000000005
      for i in range(0, N):
          if X[i] >= 0:
              break
          res = -X[i]
          k = idx_zero - i
          if (k < K) and (idx_zero + K - k - 1 < N):
              res += cumsum[idx_zero + K - k - 1] - cumsum[i]
              ret = min(ret, res)
  
      return ret
  
  
  if __name__ == "__main__":
      N, K = map(int, input().split())
      X = list(map(int, input().split()))
  
      res = 1000000005
      if min(X) >= 0:
          print(X[K - 1])
      elif max(X) <= 0:
          X = X[::-1]
          print(-X[K - 1])
      else:
          res = min(res, solve(X, K))
          X = [-x for x in X]
          res = min(res, solve(X[::-1], K))
          print(res)
  
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"}]