output_description: Print the minimum possible area of a rectangle that satisfies the condition.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N K  
      x_1 y_1
      :  
      x_{N} y_{N}
attempt:  N, K = list(map(int, input().split()))
  
   co = []
   for i in range(N):
       co.append(list(map(int, input().split())))
  
  
   S = 99999999999999999999
   for xi in range(N):
       for xj in range(N):
           for yi in range(N):
               for yj in range(N):
                   l = abs(co[xi][0] - co[xj][0])
                   m = abs(co[yi][1] - co[yj][1])
   ----------------
                   a = min(co[xi][0], co[xj][0])
                   b = max(co[xi][0], co[xj][0])
                   c = min(co[yi][1], co[yj][1])
                   d = max(co[yi][1], co[yj][1])
                   num = 0
                   for i in range(N):
                       if (a <= co[i][0] <= b) and (c <= co[i][1] <= d):
                           num += 1
                   if num >= K:
                       p = l*m
                       S = min(S,p)
   print(S)
  
problem_description: Statement
  
  We have N points in a two-dimensional plane.  
  The coordinates of the i-th point (1 \leq i \leq N) are (x_i,y_i).  
  Let us consider a rectangle whose sides are parallel to the coordinate axes
  that contains K or more of the N points in its interior.  
  Here, points on the sides of the rectangle are considered to be in the
  interior.  
  Find the minimum possible area of such a rectangle.
samples: [{"input": "4 4\n    1 4\n    3 3\n    6 2\n    8 1", "output": "21\n    \n\nOne rectangle that satisfies the condition with the minimum possible area has\nthe following vertices: (1,1), (8,1), (1,4) and (8,4).  \nIts area is (8-1) \u00d7 (4-1) = 21.\n\n* * *"}, {"input": "4 2\n    0 0\n    1 1\n    2 2\n    3 3", "output": "1\n    \n\n* * *"}, {"input": "4 3\n    -1000000000 -1000000000\n    1000000000 1000000000\n    -999999999 999999999\n    999999999 -999999999", "output": "3999999996000000001\n    \n\nWatch out for integer overflows."}]