#include<map>
#include<cmath>
#include<cstdio>
#include<iostream>
#include<algorithm>

using namespace std;

const int mod=1e8+7;

#define N 501

struct node
{
    int x,y;
}e[N+1];

map<int,int>mp;

void read(int &x)
{
    x=0; char c=getchar();
    
 
while(!isdigit(c)) c=getchar();
    while(isdigit(c)) { x=x*10+c-'0'; c=getchar(); }
}

int Pow(int a,long long b)
{
    int res=1;
    for(;b;b>>=1,a=1LL*a*a%mod)
        if(b&1) res=1LL*res*a%mod;
    return res;
}

int get_inv(int a)
{
    return Pow(a,mod-2);
}

int BSGS(int
 
 a,int b,int p)
{
    mp.clear();
    int m=sqrt(p);
    mp[b]=0;
    for(int i=1;i<=m;++i) 
    {
        b=1LL*b*a%mod;
        mp[b]=i;
    }
    int am=Pow(a,m);
    int mul=1;
    for(int i=1;i<=m;++i)
    {
        mul=1LL*mul*am%mod;
        if(mp.find(mul)!=mp.end()) return
 
 i*m-mp[mul];
    }
    return -1;
}

bool cmp(node p,node q)
{
    if(p.y!=q.y) return p.y<q.y;
    return p.x<q.x;
}

int main()
{
    int T;
    int n,k,b,r;
    int m,x,y;
    int ck,ckm;
    int a,rr;
    int ans;
    read(T);
    for(int t=1;t<=T;++t)
    {
        read(n); read(k); read(b); read(r);
        ck=ckm=n; m=0;
        for(int i=1;i<=b;++i)
        {
            read(e[i].x); read(e[i].y);
            if(e[i].x==1) ck--,ckm--;
            m=max(m,e[i].x);
        }
        sort(e+1,e+b+1,cmp);
        e[b+1].x=e[b+1].y=-1;
        for(int i=1;i<=b;++i)
            if(!(e[i].y==e[i+1].y && e[i].x==e[i+1].x-1)) 
            {
                ck++;
                if(e[i].x!=m) ckm++;
            }
        if(m)
        {
            rr=1LL*Pow(k,ckm)*Pow(k-1,1LL*n*m-b-ckm)%mod;
            if(rr==r)
            {
                printf("Case %d: %d\n",t,m);
                continue;
            }
            rr=1LL*rr*Pow(k,ck-ckm)%mod;
            rr=1LL*rr*Pow(k-1,n-(ck-ckm))%mod;
        }
        else rr=Pow(k,n);
        if(rr==r)
        {
            printf("Case %d: %d\n",t,m+1);
            continue;
        }
        r=1LL*r*get_inv(rr)%mod;
        a=BSGS(Pow(k-1,n),r,mod);
        printf("Case %d: %d\n",t,a+m+1);
    }
    return 0;
}