implicit none
integer(8) :: n,kk,i,j,k,l,s,num,m
integer(8), allocatable, dimension(:):: x,y

read (5,*) n, kk
s=9223372036854775807_8

allocate(x(n))
allocate(y(n))

do i=1, n
    read (5,*) x(i), y(i)
enddo

do i=1, n
do j=1, n
do k=1, n
do l=1, n

    num=0
    do m=1,n
        if(x(m)>=x(i) .and. x(m)<=x(j) .and. y(m)>=y(k) .and. y(m)<=y(l)) then
            num=num+1
        endif 
    enddo

    if(num>=kk) then
        S=min(S, (x(j)-x(i))*(y(l)-y(k)))
    endif
enddo
enddo
enddo
enddo

write(6,*) s

end
