object Main{
  def main(args:Array[String]) = {
    val sc = new java.util.Scanner(System.in)
    val n = sc.nextInt
    val p = sc.nextInt

    val x_ = Array.ofDim[BigInt](n)
    val y_ = Array.ofDim[BigInt](n)
    for(i <- 0 to n-1){
      x_(i) = sc.nextInt
      y_(i) = sc.nextInt
    }

    val x = x_.sorted
    val y = y_.sorted

    //println(x.deep)
    //println(y.deep)

    var ans : BigInt = (x(n-1)-x(0)) * (y(n-1)-y(0))
    for(i <- 0 to n-1){
      for(j <- i+1 to n-1){
        for(k <- 0 to n-1){
          for(l <- k+1 to n-1){
            var cnt = 0
            for(m <- 0 to n-1){
              if(x(i) <= x(m) && x(m) <= x(j) && y(k) <= y(m) && y(m) <= y(l)) cnt = cnt + 1
            }
            //val t = (x(j)-x(i)) * (y(l)-y(k))
            //println(cnt,t)
            if(cnt >= p){
              ans = ans.min((x(j)-x(i))*(y(l)-y(k)))
            }
          }
        }
      }
    }
    println(ans)
  }
}
