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

#define CPP_STR(x) CPP_STR_I(x)
#define CPP_CAT(x,y) CPP_CAT_I(x,y)
#define CPP_STR_I(args...) #args
#define CPP_CAT_I(x,y) x ## y

using i8  = int8_t;
using u8  = uint8_t;
using i16 = int16_t;
using u16 = uint16_t;
using i32 = int32_t;
using u32 = uint32_t;
using i64 = int64_t;
using u64 = uint64_t;

using f32 = float;
using f64 = double;

#define FOR(i, start, end) for(i64 i = (start), CPP_CAT(i,xxxx_end)=(end); i < CPP_CAT(i,xxxx_end); ++i)
#define REP(i, n) FOR(i, 0, n)
#define REPS(i, n) for(i64 i = 1; i <= n; ++i)
#define RREP(i, n) for(i64 i = n - 1; i >= 0 ; --i)
#define RREPS(i, n) for(i64 i = n; i >= 1; --i)

#define ALL(f,c,...) (([&](decltype((c)) cccc) { return (f)(std::begin(cccc), std::end(cccc), ## __VA_ARGS__); })(c))

#define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() );

#define pb push_back
#define mp make_pair
#define F first
#define S second

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }

template<typename C>
i64 SIZE(const C& c) { return static_cast<i64>(c.size()); }

template<typename T, size_t N>
i64 SIZE(const T (&)[N]) { return static_cast<i64>(N); }


struct ProconInit {
    static constexpr int IOS_PREC = 15;
    static constexpr bool AUTOFLUSH = false;

    ProconInit() {
        cin.tie(nullptr);
        ios::sync_with_stdio(false);
        cout << fixed << setprecision(IOS_PREC);
        if(AUTOFLUSH)
            cout << unitbuf;
    }
} PROCON_INIT;


int main() {
    i64 N, K; cin >> N >> K;
    using P = pair<i64, i64>;
    vector<P> point(N);
    map<i64, i64> mpX, mpY;
    REP(i, N) {
        cin >> point[i].first >> point[i].second;
        mpX[point[i].first] = 0;
        mpY[point[i].second] = 0;
    }

    vector<i64> xvals;
    vector<i64> yvals;
    for (auto &p : mpX) {
        p.second = xvals.size();
        xvals.pb(p.first);
    }
    for (auto &p : mpY) {
        p.second = yvals.size();
        yvals.pb(p.first);
    }

    i64 H = yvals.size() * 2;
    i64 W = xvals.size() * 2;
    vector<vector<i64>> G(H, vector<i64>(W, 0));
    REP(i, N) {
        i64 y = mpY[point[i].second] * 2;
        i64 x = mpX[point[i].first] * 2;
        G[y][x] = 1;
    }

    vector<vector<i64>> C(H + 1, vector<i64>(W + 1, 0));
    REP(y, H) {
        REP(x, W) {
            C[y + 1][x + 1] = C[y][x + 1] + C[y + 1][x] - C[y][x] + G[y][x];
        }
    }

    i64 mins = numeric_limits<i64>::max();
    REP(i, N) REP(j, N) REP(k, N) REP(l, N) {
        i64 minx, miny, maxx, maxy;
        minx = maxx = point[i].first;
        miny = maxy = point[i].second;

        auto update = [&](i64 idx) {
            chmin(minx, point[idx].first);
            chmax(maxx, point[idx].first);
            chmin(miny, point[idx].second);
            chmax(maxy, point[idx].second);
        };
        update(j), update(k), update(l);

        i64 clx, cly, crx, cry;
        clx = mpX[minx] * 2;
        cly = mpY[miny] * 2;
        crx = mpX[maxx] * 2 + 1;
        cry = mpY[maxy] * 2 + 1;
        i64 cnt = C[cry][crx] - C[cry][clx] - C[cly][crx] + C[cly][clx];
        if (cnt >= K) {
            i64 dx = abs(maxx - minx);
            i64 dy = abs(maxy - miny);
            if (dx * dy > 0) chmin(mins, dx * dy);
        }
    }

    cout << mins << endl;

    return 0;
}

Measured memory_bytes: 384