Code is Successfully Executed, but on Submission shows Wrong Answer. problemcode:entexam

#include
#include
using namespace std;
int main()
{
int tests;
cin>>tests;
for(int tno=0;tno<tests;tno++)
{
int n,k,e,m;
int score;
int ser[50],sertot=0,total[50]={0},temp=0;

        cin>>n>>k>>e>>m;

        for(int i=0;i<n-1;i++)
        {
            for(int j=0;j<e;j++)
            {
                cin>>score;
                total[i]=total[i]+score;
            }
            }
        for(int j=0;j<e-1;j++)
        {
            cin>>ser[j];
            sertot+=ser[j];
        }

        sort(total,total+n-1,greater<int>());


        temp=total[k-1];
        if(temp >= sertot)
        {
            int need;
            need=temp-sertot;
            if(need<=m)
                cout<<need+1;
            else
                cout<<"impossible";
        }
        else
           {
            cout<<"0";
           }
    }
    return 0;
}