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

immutable mod = 10^^9 + 7;
immutable inf = 2 * 10^^9;

void main() {
    int n, k;
    scan(n, k);

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

    foreach (i ; 0 .. n) {scan(x[i], y[i]);}

    long ans = long.max;
    bool[] mask = new bool[](n);

    void dfs(int xl, int xr, int yb, int yt, int take) {
        if (take == k || take == 4) {
            int cnt;

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

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

            return;
        }

        foreach (i ; 0 .. n) {
            if (!mask[i]) {
                mask[i] = 1;
                dfs(min(xl, x[i]), max(xr, x[i]), min(yb, y[i]), max(yt, y[i]), take + 1);
                mask[i] = 0;
            }
        }
    }

    dfs(inf, -inf, inf, -inf, 0);

    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);
        }
    }
}