#include "bits/stdc++.h"
using namespace std;

int main() {
	int N, K;
	long long ans = pow(2, 63) - 513;
	pair<long long, long long> P[50];
	cin >> N >> K;
	for (int i = 0; i < N; i++) {
		cin >> P[i].first >> P[i].second;
	}
	for (int i = 0; i < N; i++) {
		for (int j = i; j < N; j++) {
			for (int k = 0; k < N; k++) {
				for (int l = k; l < N; l++) {
					long long xl = min(P[i].first, P[j].first), xr = max(P[i].first, P[j].first);
					long long yu = min(P[k].second, P[l].second), yd = max(P[k].second, P[l].second);
					int count = 0;
					for (int m = 0; m < N; m++) {
						if (xl <= P[m].first && P[m].first <= xr && yu <= P[m].second && P[m].second <= yd) count++;
					}
					if (count >= K) ans = min(ans, (xr - xl) * (yd - yu));
				}
			}
		}
	}
	cout << ans;
}