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=map(int,input().split())
  z=[tuple(map(int,input().split()))for _ in range(N)]
  x=[i for i,_ in z]
  y=[j for _,j in z]
  x.sort()
  y.sort()
  a=10**20
  for i in range(N):
      for j in range(i+1,N):
          for k in range(N):
              for l in range(k+1,N):
                  l,r,d,u=x[i],x[j],y[k],y[l]
                  if sum([1for v,w in z if l<=v<=r and d<=w<=u else 0])>=K:
                      a=min(a,(r-l)*(u-d))
  print(a)
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."}]