#include <bits/stdc++.h>
using namespace std;
int main() 
{
    cin.tie(NULL);
    cout.tie(NULL);
    ios_base::sync_with_stdio(false);
    long int t;
    cin>>t;
    while(t--)
    {
        long int x,y,n,k;
        cin>>x>>y>>n>>k;
        long int flag=0;
        long int pagesNeeded=x-y;
        for(int i=0;i<n;i++)
        {
            long int p,c;
            cin>>p>>c;
            if(p>=pagesNeeded && c<=k)
            flag=1;
        }
        if(flag==0)
        cout<<"UnluckyChef"<<endl;
        else
        cout<<"LuckyChef"<<endl;
 
    }
	return 0;
}
 

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3
3 1 2 2
3 4
2 2    
3 1 2 2
2 3
2 3    
3 1 2 2
1 1
1 2