#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <array>
#include <queue>
#include <deque>
#include <map>
#include <set>
#include <sstream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <list>
#include <numeric>
#include <stack>
#include <iomanip>
#include <random>
#include <complex>
#include <functional>
#include <tuple>

using namespace std;

#define Rep(i,a,b) for(int i = a; i < b; ++i)
#define rep(i,b) Rep(i,0,b)
#define allof(a) (a).begin(), (a).end()

#define Yes(q) ((q) ? "Yes" : "No")
#define YES(q) ((q) ? "YES" : "NO")
#define Possible(q) ((q) ? "Possible" : "Impossible")
#define POSSIBLE(q) ((q) ? "POSSIBLE" : "IMPOSSIBLE")

using ll = long long;

using pint = std::pair<int, int>;
using pll = std::pair<ll, ll>;


constexpr int inf = 1e9 + 7;
constexpr ll infll = 1ll << 62ll;
constexpr ll mod = 1e9 + 7;
// 0~3までは右左下上 4~7までは斜め
constexpr int dx[] = { 1, 0, -1, 0, 1, 1, -1, -1 };
constexpr int dy[] = { 0, -1, 0, 1, 1, -1, -1, 1 };

namespace {
    template<typename T> void chmax(T& a, T b) { a = std::max(a, b); }
    template<typename T> void chmin(T& a, T b) { a = std::min(a, b); }
    template<typename T> void chadd(T& a, T b) { a = a + b; }

    void Cout(long long x, const char* end = "\n") { std::cout << x << end; }
    template <typename T> void Cout(const T& x, const char* end = "\n") { std::cout << x << end; }
    template <typename T> void Cout(const std::vector<T>& x, const char* sep = " ", const char* end = "\n") { for (std::size_t i = 0, sz = x.size(); i < sz; i++) { std::cout << x[i] << (i == sz - 1 ? end : sep); } }

    void CCout(long long x, const char* end = "\n") { std::cerr << x << end; }
    template <typename T> void CCout(const T& x, const char* end = "\n") { std::cerr << x << end; }
    template <typename T> void CCout(const std::vector<T>& x, const char* sep = " ", const char* end = "\n") { for (std::size_t i = 0, sz = x.size(); i < sz; i++) { std::cerr << x[i] << (i == sz - 1 ? end : sep); } }

    // 標準入出力
    struct inp {
        std::size_t sz;
        inp(std::size_t _sz = 1) : sz(_sz) {}
        template <typename T> operator T () const { T a; std::cin >> a; return a; }
        template <typename T> operator std::vector<T>() const { vector<T> a(sz); for (std::size_t i = 0; i < sz; i++) std::cin >> a[i]; return a; }
        template <typename T, typename U> operator std::pair<T, U>() const { T f; U s; std::cin >> f >> s; return std::pair<T, U>(f, s); }
    };

    inp inp1; // input one

    template<class T>
    class CulSum2D {
    private:
        //original
        int H, W;

        //original+1
        vector<vector<T>> data;

    public:

        /// @param _H original
        /// @param _W original
        CulSum2D(int _H, int _W) :
            H(_H), W(_W) {
            reset();
        }

        void reset() {
            data = vector<vector<T>>(H + 1, vector<T>(W + 1, T{}));
        }

        /// 0-index
        /// @param y original
        /// @param x original
        /// @param d original
        void add(T y, T x, T d) {
            y++;
            x++;
            if (y >= H + 1 || x >= W + 1) return;
            data[y][x] += d;
        }

        void build() {
            for (int i = 0; i < H; i++) {
                for (int j = 0; j < W; j++) {
                    data[i + 1][j + 1] += data[i + 1][j] + data[i][j + 1] - data[i][j];
                }
            }
        }

        /// 0-index
        /// @param sy original close
        /// @param sx original close
        /// @param ty original open
        /// @param tx original open
        T get(int sy, int sx, int ty, int tx) {
            return data[ty][tx] - data[ty][sx] - data[sy][tx] + data[sy][sx];
        }

    };
}

int main() {

    int n, K;
    cin >> n >> K;
    vector<ll> x(n), y(n);
    rep(i, n) cin >> x[i] >> y[i];

    ll ans = infll;

    // 全探索
    vector<ll> lefts(n);
    vector<ll> rights(n);
    vector<ll> tops(n);
    vector<ll> bottoms(n);
    rep(i, n) {
        lefts[i] = x[i];
        rights[i] = x[i];
        tops[i] = y[i];
        bottoms[i] = y[i];
    }

    sort(allof(lefts));
    sort(allof(rights), greater<ll>());
    sort(allof(bottoms));
    sort(allof(tops), greater<ll>());

    CulSum2D<ll> sum(n, n);
    rep(i, n) {
        ll tx = lefts[i];
        // これを基にyを求める
        int xi = 0;
        rep(j, n) if (x[j] == tx) {
            xi = j;
            break;
        }
        ll ty = y[xi];
        int yi = 0;
        rep(j, n) if (bottoms[j] == ty) {
            yi = j;
            break;
        }
        sum.add(yi, i, 1);
    }

    sum.build();

    // どこまで縮めるか
    rep(xi, n) {
        rep(xj, n - xi - 1) {
            rep(yi, n) {
                rep(yj, n - yi - 1) {
                    ll left = lefts[xi];
                    ll right = rights[xj];
                    ll bottom = bottoms[yi];
                    ll top = tops[yj];

                    // 何点含まれているか
                    int cnt = 0;
                    cnt = sum.get(yi, xi, n - yj, n - xj);
                    //cout << "cnt : " << cnt << " left : " << left << ", right : " << right;
                    //cout << ", bottom : " << bottom << ", top : " << top << ", mes : " << (right - left) * (top - bottom) << endl;

                    if (cnt >= K) {
                        chmin(ans, (right - left)* (top - bottom));
                    }
                }
            }
        }
    }

    Cout(ans);

    return 0;
}

Measured memory_bytes: 256