Problem 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.

Constraints

• $2 \\leq K \\leq N \\leq 50$
• $\-10^9 \\leq x_i,y_i \\leq 10^9 (1 \\leq i \\leq N)$
• $x_i≠x_j (1 \\leq i<j \\leq N)$
• $y_i≠y_j (1 \\leq i<j \\leq N)$
• All input values are integers. (Added at 21:50 JST)

Input

Input is given from Standard Input in the following format:

$N$ $K$
$x_1$ $y_1$ $:$
$x_{N}$ $y_{N}$

Output

Print the minimum possible area of a rectangle that satisfies the condition.

Sample Input 1

4 4
1 4
3 3
6 2
8 1

Sample Output 1

21

One rectangle that satisfies the condition with the minimum possible area has the following vertices: $(1,1)$, $(8,1)$, $(1,4)$ and $(8,4)$.
Its area is $(8-1) × (4-1) = 21$.

Sample Input 2

4 2
0 0
1 1
2 2
3 3

Sample Output 2

1

Sample Input 3

4 3
-1000000000 -1000000000
1000000000 1000000000
-999999999 999999999
999999999 -999999999

Sample Output 3

3999999996000000001

Watch out for integer overflows.