#include <bits/stdc++.h>
using namespace std;
typedef long long  ll;

int main(){
	int n, K;
	cin >> n >> K;
	vector<ll>x(n), y(n);
	for (int i = 0;i < n;i++) {
		cin >> x[i] >> y[i];
	}

	ll ans = 4e18;
	for (int i = 0;i < n;i++) {
		for (int j = 0;j < n;j++) {
			for (int k = 0;k < n;k++) {
				for (int l = 0;l < n;l++) {
					ll minx = min(min(x[i], x[j]), min(x[k], x[l]));
					ll maxx = max(max(x[i], x[j]), max(x[k], x[l]));
					ll miny = min(min(y[i], y[j]), min(y[k], y[l]));
					ll maxy = max(max(y[i], y[j]), max(y[k], y[l]));
					int count = 0;
					for (int m = 0;m < n;m++) {
						if (x[m] >= minx && x[m] <= maxx && y[m] >= miny && y[m] <= maxy) {
							count++;
						}
					}
					if (count >= K) {
						ans = min(ans, (maxx - minx)*(maxy - miny));
					}
				}
			}
		}
	}
	cout << ans << endl;

	return 0;
}