Buggy python submission (verdict: Time Limit Exceeded):
from collections import defaultdict,deque
import sys,heapq,bisect,math,itertools,string,queue,datetime
sys.setrecursionlimit(10**8)
INF = float('inf')
mod = 10**9+7
def inpl(): return list(map(int, input().split()))
def inpls(): return list(input().split())

N,K = inpl()
xys = []
xx = set()
yy = set()
for i in range(N):
    x,y = inpl()
    xys.append([x,y])
    xx.add(x)
    yy.add(y)

ans = INF
xx = sorted(list(xx))
yy = sorted(list(yy))
Lx = len(xx)
Ly = len(yy)
for i1 in range(Lx):
    x1 = xx[i1]
    for i2 in range(i1,Lx):
        x2 = xx[i2]
        for j1 in range(Ly):
            y1 = yy[j1]
            for j2 in range(j1,Ly):
                y2 = yy[j2]
                tmp = 0
                for x,y in xys:
                    if x1 <= x <= x2 and y1 <= y <= y2:
                        tmp += 1
                if K <= tmp:
                    ans = min(ans,(x2-x1)*(y2-y1))

print(ans)


Fixed submission:
from collections import defaultdict,deque
import sys,heapq,bisect,math,itertools,string,queue,datetime
sys.setrecursionlimit(10**8)
INF = float('inf')
mod = 10**9+7
def inpl(): return list(map(int, input().split()))
def inpls(): return list(input().split())

N,K = inpl()
xys = []
xx = set()
for i in range(N):
    x,y = inpl()
    xys.append([x,y])
    xx.add(x)

ans = INF
xx = sorted(list(xx))
Lx = len(xx)
xys.sort(key = lambda x: x[1])
for i1 in range(Lx):
    x1 = xx[i1]
    for i2 in range(i1,Lx):
        x2 = xx[i2]
        yy = []
        for x,y in xys:
            if x1 <= x <= x2:
                yy.append(y)
        Ly = len(yy)
        if Ly < K:
            continue
        else:
            for l in range(Ly-K+1):
                r = l+K-1
                ans = min((yy[r]-yy[l])*(x2-x1),ans)

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
from collections import defaultdict
import sys,heapq,bisect,math,itertools,string,queue,datetime
sys.setrecursionlimit(10**8)
INF = float('inf')
mod = 10**9+7
eps = 10**-7
AtoZ = [chr(i) for i in range(65,65+26)]
atoz = [chr(i) for i in range(97,97+26)]

def inpl(): return list(map(int, input().split()))
def inpl_s(): return list(input().split())

N,K = inpl()
xys = []
xx = []
yy = []
ans = INF

for i in range(N):
	x,y = inpl()
	xys.append([x,y])

xys.sort()
for x,y in xys:
	xx.append(x)
	yy.append(y)



for i1 in range(N):
	for j1 in range(N):
		for i2 in range(i1+1,N):
			for j2 in range(j1+1,N):
				x1,x2 = xx[i1],xx[i2]
				y1,y2 = yy[j1],yy[j2]
				if y1 > y2:
					y1,y2 = y2,y1
				tmp = 0
				for ix in range(i1,i2+1):
					y = xys[ix][1]
					if y1 <= y <= y2:
						tmp += 1
				if tmp == K:
					S = abs(x1-x2)*abs(y1-y2)
					ans = min(ans,S)

print(ans)

Fixed submission:
from collections import defaultdict,deque
import sys,heapq,bisect,math,itertools,string,queue,datetime
sys.setrecursionlimit(10**8)
INF = float('inf')
mod = 10**9+7
def inpl(): return list(map(int, input().split()))
def inpls(): return list(input().split())

N,K = inpl()
xys = []
xx = set()
for i in range(N):
    x,y = inpl()
    xys.append([x,y])
    xx.add(x)

ans = INF
xx = sorted(list(xx))
Lx = len(xx)
xys.sort(key = lambda x: x[1])
for i1 in range(Lx):
    x1 = xx[i1]
    for i2 in range(i1,Lx):
        x2 = xx[i2]
        yy = []
        for x,y in xys:
            if x1 <= x <= x2:
                yy.append(y)
        Ly = len(yy)
        if Ly < K:
            continue
        else:
            for l in range(Ly-K+1):
                r = l+K-1
                ans = min((yy[r]-yy[l])*(x2-x1),ans)

print(ans)