output_description: Format
  
  Print the minimum cost in one line. In the end put a line break.
input_description: Format
  
      
      
      N K
      a_1 a_2 a_3 ... a_N
attempt: N, K = list(map(int, input().split()))
  height = list(map(int, input().split()))
  height2=height.copy()
  ans = 10 ** 10
  # if N==K:
  #     cost=0
  #     for i in range(1,N):
  #         if height2[i-1]>=height2[i]:
  #             cost+=height2[i-1]-height2[i]+1
  #             height2[i]+=height2[i-1]-height2[i]+1
  #     print(cost)
  for i in range(2 ** N):
      count=1
      cost = 0
      height2 = height.copy()
      if bin(i).count("1")>=K:
          for j in range(N):
              if i >> j & 1:
                  if j!=0:
                      tarou=max(height2[:j])
                      if height2[j]<=tarou:
                          cost+=tarou-height2[j]+1
                          height2[j]+=tarou-height2[j]+1
  
          if ans > cost
              ans = cost
  
  print(ans)
problem_description: Statement
  
  There are N buildings along the line. The i-th building from the left is
  colored in color i, and its height is currently a_i meters.  
  Chokudai is a mayor of the city, and he loves colorful thigs. And now he wants
  to see at least K buildings from the left.  
    
  You can increase height of buildings, but it costs 1 yens to increase 1
  meters. It means you cannot make building that height is not integer.  
  You cannot decrease height of buildings.  
  Calculate the minimum cost of satisfying Chokudai's objective.  
  Note: "Building i can see from the left" means there are no j exists that
  (height of building j) ≥ (height of building i) and j < i.
samples: [{"input": "5 5\n    3949 3774 3598 3469 3424", "output": "1541\n    \n\nThe optimal solution is (height of buildings from the left) = [3949, 3950,\n3951, 3952, 3953]."}, {"input": "5 3\n    7 4 2 6 4", "output": "7\n    \n\nThe optimal solution is (height of buildings from the left) = [7, 8, 2, 9, 4]."}]