#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#define inf 1072114514
#define llinf 8101145141919364364
#define mod 1000000007

int max(int a,int b){if(a>b){return a;}return b;}
int min(int a,int b){if(a<b){return a;}return b;}
int zt(int a,int b){return max(a,b)-min(a,b);}
int round(int a,int b){if((a%b)*2 >= b){return (a/b)+1;}return a/b;}
int ceil(int a,int b){if(a%b==0){return a/b;}return (a/b)+1;}
int gcd(int a,int b){int c;while(b!=0){c=a%b;a=b;b=c;}return a;}
int lcm(int a,int b){int c=gcd(a,b);a/=c;return a*b;}
int nCr(int a,int b){int i,r=1;for(i=1;i<=b;i++){r*=(a+1-i);r/=i;}return r;}
int fact(int a){int i,r=1;for(i=1;i<=a;i++){r*=i;}return r;}
int pow(int a,int b){int i,r=1;for(i=1;i<=b;i++){r*=a;}return r;}
long long llmax(long long a,long long b){if(a>b){return a;}return b;}
long long llmin(long long a,long long b){if(a<b){return a;}return b;}
long long llzt(long long a,long long b){return llmax(a,b)-llmin(a,b);}
long long llround(long long a,long long b){if((a%b)*2 >= b){return (a/b)+1;}return a/b;}
long long llceil(long long a,long long b){if(a%b==0){return a/b;}return (a/b)+1;}
long long llgcd(long long a,long long b){long long c;while(b!=0){c=a%b;a=b;b=c;}return a;}
long long lllcm(long long a,long long b){long long c=llgcd(a,b);a/=c;return a*b;}
long long llnCr(long long a,long long b){long long i,r=1;for(i=1;i<=b;i++){r*=(a+1-i);r/=i;}return r;}
long long llfact(long long a){long long i,r=1;for(i=1;i<=a;i++){r*=i;}return r;}
long long llpow(long long a,long long b){long long i,r=1;for(i=1;i<=b;i++){r*=a;}return r;}
double dbmax(double a,double b){if(a>b){return a;}return b;}
double dbmin(double a,double b){if(a<b){return a;}return b;}
double dbzt(double a,double b){return dbmax(a,b)-dbmin(a,b);}
int sortfncsj(const void *a,const void *b){if(*(int *)a>*(int *)b){return 1;}if(*(int *)a==*(int *)b){return 0;}return -1;}
int sortfnckj(const void *a,const void *b){if(*(int *)a<*(int *)b){return 1;}if(*(int *)a==*(int *)b){return 0;}return -1;}
int llsortfncsj(const void *a,const void *b){if(*(long long *)a>*(long long *)b){return 1;}if(*(long long *)a==*(long long *)b){return 0;}return -1;}
int llsortfnckj(const void *a,const void *b){if(*(long long *)a<*(long long *)b){return 1;}if(*(long long *)a==*(long long *)b){return 0;}return -1;}
int dbsortfncsj(const void *a,const void *b){if(*(double *)a>*(double *)b){return 1;}if(*(double *)a==*(double *)b){return 0;}return -1;}
int dbsortfnckj(const void *a,const void *b){if(*(double *)a<*(double *)b){return 1;}if(*(double *)a==*(double *)b){return 0;}return -1;}

typedef struct{
long long pn;
long long zh;
}data;
 
int sortfnc(const void *a,const void *b){
if(((data*)a)->zh == ((data*)b)->zh){return 0;}
if(((data*)a)->zh < ((data*)b)->zh){return -1;}
return 1;
}

int main(void){
    long long n,k,x[64],y[64],i,j,p,q,r=llinf,c,a;
    long long xr[64],yr[64];
    data xd[64],yd[64];
    scanf("%lld%lld",&n,&k);
    for(i=0;i<n;i++){
        scanf("%lld%lld",&x[i],&y[i]);
        xd[i].pn=i;xd[i].zh=x[i];
        yd[i].pn=i;yd[i].zh=y[i];
    }
    qsort(xd,n,sizeof(data),sortfnc);
    qsort(yd,n,sizeof(data),sortfnc);
    for(i=0;i<n;i++){
        xr[xd[i].pn]=i;yr[yd[i].pn]=i;
    }
    for(i=0;i<n;i++){
        for(j=i+1;j<n;j++){
            for(p=0;p<n;p++){
                for(q=p+1;q<n;q++){
                    c=0;
                    for(a=0;a<n;a++){
                        if(i <= xr[a] && xr[a] <= j && p <= yr[a] && yr[a] <= q){c++;}
                    }
                    if(c<k){continue;}
                    r = llmin(r,llzt(xd[i].zh,xd[j].zh)*llzt(yd[p].zh,yd[q].zh));
                }
            }
        }
    }
    printf("%lld\n",r);
    return 0;
}

Measured memory_bytes: 128