import std.stdio;
import std.typecons;
import std.algorithm;
import std.conv;

alias Tuple!(long,long) coord;

void main() {
	int K, N;
	coord [] pts;
	long [] xs;
	readf("%d %d\n", &N, &K);
	for(int i = 0; i < N; i++) {
		long x, y;
		readf("%d %d\n", &x, &y);
		pts ~= coord(x,y);
		xs ~= x;
	}

	sort(xs);
	long res = 5_000_000_000_000_000_000L;
	for(int i = 0; i < xs.length; i++) {
		for(int j = i; j < xs.length; j++) {
			long [] ys;
			for(int k = 0; k < pts.length; k++) {
				if(xs[i] <= pts[k][0] && pts[k][0] <= xs[j])
					ys ~= pts[k][1];
			}
			sort(ys);
			for(int k = 0; k+K-1 < ys.length; k++)
				res = min(res, (xs[j]-xs[i])*(ys[k+K-1]-ys[k]));
		}
	}
	writeln(res);
}

