/*********************************************************

*      --------------Alfheim--------------               *

*   author AbyssalFish                                   *

**********************************************************/

#include<bits/stdc++.h>

using namespace std;

typedef long long ll;

const int maxn = 3e4+;

const int maxnc = maxn*;

const int maxk = ;

int x[maxnc], y[maxnc];

int xs[maxnc], mpx[maxnc];

int rx[maxnc], ry[maxnc];

int n, nxs, lim_k;

#define para int o = 1, int l = 1, int r = nxs

#define lo (o<<1)

#define ro (o<<1|1)

#define Tvar int md = (l+r)>>1;

#define lsn lo,l,md

#define rsn ro,md,r

#define insd ql<=l&&r<=qr

const int ST_SIZE = <<;

int sum[ST_SIZE][maxk+];

int cnt[ST_SIZE];

#define int_byte 4

void build(para)

{

    cnt[o] = ;

    memset(sum[o]+,,int_byte*lim_k);

    sum[o][] = mpx[r]-mpx[l];

    if(r-l>){

        Tvar

        build(lsn);

        build(rsn);

    }

}

inline void maintain(para)

{

    if(cnt[o] >= lim_k) {

        memset(sum[o],,int_byte*lim_k);

        sum[o][lim_k] = mpx[r]-mpx[l];

    }

    else if(r - l == ) {

        int k = cnt[o];

        sum[o][k] = mpx[r]-mpx[l];

        if(k > ) sum[o][k-] = ;

        if(k < lim_k) sum[o][k+] = ;

    }

    else {

        int lc = lo, rc = ro, c = cnt[o], k;

        for(k = ; k < c; k++) sum[o][k] = ;

        for(k = c; k <= lim_k; k++){

            sum[o][k] = sum[lc][k-c] + sum[rc][k-c];

        }

        for(k = lim_k - c+; k <= lim_k; k++){

            sum[o][lim_k] += sum[lc][k] + sum[rc][k];

        }

    }

}

#define upara ql,  qr,  d

void update(int ql, int qr, int d, para)

{

    if(insd){

        cnt[o] += d;

    }

    else {

        Tvar

        if(ql < md) update(upara,lsn);

        if(qr > md) update(upara,rsn);

    }

    maintain(o,l,r);

}

int *c_cmp;

bool cmp_id(int i,int j){ return c_cmp[i] < c_cmp[j]; }

bool cmp_y(int i,int j){ return y[i] < y[j] || (y[i] == y[j] && (i&)>(j&) ); } //出点下标i, i % 2 = 1

int compress(int n, int *a, int *r, int *b, int *mp)

{

    for(int i = ; i < n; i++){

        r[i] = i;

    }

    c_cmp = a;

    sort(r,r+n,cmp_id);

    int k = ;

    mp[b[r[]] = ] = a[r[]];

    for(int i = ; i < n; i++){

        int j = r[i];

        if(a[j] != a[r[i-]]){

            mp[ b[j] = ++k ] = a[j];

        }

        else {

            b[j] = k;

        }

    }

    return k;

}

ll solve()

{

    scanf("%d%d",&n,&lim_k);

    int nn = n*;

    for(int i = ; i < nn; i++){

        scanf("%d%d",x+i,y+i);

        ry[i] = i;

    }

    for(int i = ; i < nn; i += ){ //[)

        x[i]++; y[i]++;

    }

    nxs = compress(*n,x,rx,xs,mpx);

    build();

    sort(ry,ry+nn,cmp_y);

    ll res = ;

    for(int i = ; i < nn; i++){

        int p = ry[i], q = p^;

        if(i) res += (ll)sum[][lim_k]*(y[p]-y[ry[i-]]);

        if(y[p] < y[q]){

            //assert((q&1) == 1);

            update(xs[p],xs[q],);

        }

        else {

            update(xs[q],xs[p],-);

        }

    }

    return res;

}

//#define LOCAL

int main()

{

#ifdef LOCAL

    freopen("in.txt","r",stdin);

#endif

    //cout<<log2(maxnc);

    int T, ks = ; scanf("%d",&T);

    while(++ks <= T){

        printf("Case %d: %lld\n",ks,solve());

    }

    return ;

}