output_description: Among A, B and C, print the integer that is different from the rest.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      A B C
attempt: # coding: utf-8
  # hello worldと表示する
  # float型を許すな
  # numpyはpythonで
  import sys
  
  input = sys.stdin.readline
  sys.setrecursionlimit(10**7)
  from collections import Counter, deque
  from collections import defaultdict
  from itertools import combinations, permutations, accumulate, groupby, product
  from bisect import bisect_left, bisect_right
  from heapq import heapify, heappop, heappush
  from math import floor, ceil, pi, factorial
  from operator import itemgetter
  
  
  def I():
      return int(input())
  
  
  def MI():
      return map(int, input().split())
  
  
  def LI():
      return list(map(int, input().split()))
  
  
  def LI2():
      return [int(input()) for i in range(n)]
  
  
  def MXI():
      return [[LI()] for i in range(n)]
  
  
  def SI():
      return input().rstrip()
  
  
  def printns(x):
      print("\n".join(x))
  
  
  def printni(x):
      print("\n".join(list(map(str, x))))
  
  
  inf = 10**17
  mod = 10**9 + 7
  
  n, k = MI()
  lis = [LI() for i in range(n)]
  lis.sort()
  s = []
  for i in range(n):
      for j in range(n):
          for k in range(n):
              for l in range(n):
                  xl = min(lis[i][0], lis[j][0])
                  xu = max(lis[i][0], lis[j][0])
                  yl = min(lis[k][1], lis[l][1])
                  yu = max(lis[k][1], lis[l][1])
                  count = 0
                  for m in range(n):
                      if xl <= lis[m][0] <= xu and yl <= lis[m][1] <= yu:
                          count += 1
                  if count >= k:
                      s.append((xu - xl) * (yu - yl))
  print(max(s))
  
problem_description: Statement
  
  You are given three integers, A, B and C.  
  Among them, two are the same, but the remaining one is different from the
  rest.  
  For example, when A=5,B=7,C=5, A and C are the same, but B is different.  
  Find the one that is different from the rest among the given three integers.
samples: [{"input": "5 7 5", "output": "7\n    \n\nThis is the same case as the one in the statement.\n\n* * *"}, {"input": "1 1 7", "output": "7\n    \n\nIn this case, C is the one we seek.\n\n* * *"}, {"input": "-100 100 100", "output": "-100"}]