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)

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

-----Sample Input-----
4 4
1 4
3 3
6 2
8 1

-----Sample Output-----
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.

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