#include <bits/stdc++.h>
using namespace std;
#define int long long
using ll=long long;
using vi=vector<int>;
using pii=pair<int,int>;
#define ALL(c) begin(c),end(c)
#define RALL(c) rbegin(c),rend(c)
#define ITR(i,b,e) for(auto i=(b);i!=(e);++i)
#define FORE(x,c) for(auto &x:c)
#define REPF(i,a,n) for(int i=a,i##len=(int)(n);i<i##len;++i)
#define REP(i,n) REPF(i,0,n)
#define REPR(i,n) for(int i=(int)(n);i>=0;--i)
#define SZ(c) ((int)c.size())
#define CONTAIN(c,x) (c.find(x)!=end(c))
#define OUTOFRANGE(y,x,h,w) (y<0||x<0||y>=h||x>=w)
#define dump(...)
const int DX[9]={0,1,0,-1,1,1,-1,-1,0},DY[9]={-1,0,1,0,-1,1,1,-1,0};
#define INF (1001001001)
#define INFLL (1001001001001001001ll)
template<class T> ostream& operator << (ostream &os,const vector<T> &v) {
    ITR(i,begin(v),end(v)) os<<*i<<(i==end(v)-1?"":"\n"); return os; }
template<class T> istream& operator >> (istream &is,vector<T> &v) {
    ITR(i,begin(v),end(v)) is>>*i; return is; }
template<class T> istream& operator >> (istream &is, pair<T,T> &p) {
    is>>p.first>>p.second; return is; }
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 <class T> using heap = priority_queue<T,vector<T>,greater<T>>;
struct before_main_function {
    before_main_function() {
        #ifdef int
            #undef INF
            #define INF INFLL
            #define stoi stoll
        #endif
        cin.tie(0);ios::sync_with_stdio(false);
        cout<<setprecision(15)<<fixed;
        #define endl "\n"
    }
} before_main_function;
//------------------8<------------------------------------8<--------------------

signed main() {
    int N,K;
    cin>>N>>K;
    vector<int> x(N);
    vector<int> y(N);
    vector<pii> p(N);
    map<int,int> xpos;
    map<int,int> ypos;
    REP(i,N) {
        cin>>x[i]>>y[i];
        p[i]={x[i],y[i]};
    }
    sort(ALL(x));
    x.erase(unique(ALL(x)),end(x));
    sort(ALL(y));
    y.erase(unique(ALL(y)),end(y));

    auto getx=[&](int xx) {
        return distance(begin(x),lower_bound(ALL(x),xx));
    };
    auto gety=[&](int yy) {
        return distance(begin(y),lower_bound(ALL(y),yy));
    };
    
    REP(i,N) {
        int xx=getx(p[i].first);
        int yy=gety(p[i].second);
        xpos[xx]=p[i].first;
        ypos[yy]=p[i].second;
    }

    int H=SZ(y);
    int W=SZ(x);
    vector<vector<int>> sum(H,vector<int>(W,0));
    REP(i,N) {
        int ix=getx(p[i].first);
        int iy=gety(p[i].second);
        sum[iy][ix]++;
    }
    REP(i,H) REPF(j,1,W) sum[i][j]+=sum[i][j-1];
    REP(i,W) REPF(j,1,H) sum[j][i]+=sum[j-1][i];

    auto get_cnt=[&](int y1,int x1,int y2,int x2) {
        int tmp=sum[y2][x2];
        if(x1>0) tmp-=sum[y2][x1-1];
        if(y1>0) tmp-=sum[y1-1][x2];
        if(x1>0 && y1>0) tmp+=sum[y1-1][x1-1];
        return tmp;
    };

    int ans=INF*5;
    REP(i,H) {
        REP(j,W) {
            REPF(ii,i,H) {
                REPF(jj,j,W) {
                    int t=get_cnt(i,j,ii,jj);
                    if(t>=K) {
                        int iipos=ypos[ii];
                        int ipos=ypos[i];
                        int jjpos=xpos[jj];
                        int jpos=xpos[j];
                        chmin(ans,(iipos-ipos)*(jjpos-jpos));
                    }
                }
            }
        }
    }
    cout<<ans<<endl;
    return 0;
}


Measured memory_bytes: 256