import std.stdio, std.string, std.conv, std.algorithm;
import std.range, std.array, std.math, std.typecons, std.container, core.bitop;


void main() {
    int N, K;
    scan(N, K);

    auto x = new int[](N), y = new int[](N);

    iota(N).each!(i => scan(x[i], y[i]));

    auto xa = x.dup().sort(), ya = y.dup().sort();

    long ans = 1L * (xa[$ - 1] - xa[0]) * (ya[$ - 1] - ya[0]);

    foreach (xi ; 0 .. N) {
        foreach (xj ; xi + 1 .. N) {
            foreach (yi ; 0 .. N) {
                foreach (yj ; yi + 1 .. N) {
                    int xl = xa[xi], xr = xa[xj];
                    int yb = ya[yi], yt = ya[yj];

                    int cnt;
                    foreach (l ; 0 .. N) {
                        if (xl <= x[l] && x[l] <= xr && yb <= y[l] && y[l] <= yt) cnt++;
                    }

                    if (cnt >= K) {
                        ans = min(ans, 1L * (xr - xl) * (yt - yb));
                    }
                }
            }
        }
    }

    writeln(ans);
}



void scan(T...)(ref T args) {
    string[] line = readln.split;
    foreach (ref arg; args) {
        arg = line.front.to!(typeof(arg));
        line.popFront();
    }
    assert(line.empty);
}



void fillAll(R, T)(ref R arr, T value) {
    static if (is(typeof(arr[] = value))) {
        arr[] = value;
    }
    else {
        foreach (ref e; arr) {
            fillAll(e, value);
        }
    }
}