//my code is satisfying all conditions but still giving wrong answer
#include<bits/stdc++.h>
using namespace std;
int main()
{
int t;
cin>>t;
while(t–)
{
long int n,k,e,m,i,j,ans;
long int a,sum;
cin>>n>>k>>e>>m;
long int sum1=0;
long int A[10001]={0};
for(i=1;i<n;i++)
{sum=0;
for(j=0;j<e;j++)
{
cin>>a;
sum+=a;
}
A[i]=sum;
}
for(j=0;j<e-1;j++)
{
cin>>a;
sum1+=a;
}
sort(A,A+(n));
ans= (A[k]-sum1)+1;
if(ans>m)
cout<<“Impossible”<<endl;
if((ans<=m)&&ans>0)
cout<<ans<<endl;
else
cout<<0<<endl;
// cout<<"Impossible"<<endl;
}
}