#define filer() freopen("in.txt","r",stdin)
#define filew() freopen("out.txt","w",stdout)

#include<iostream>
#include<stdio.h>
#include<string.h>
#include<math.h>
#include<algorithm>
#include<queue>
#include<stack>
#include<vector>
#include <map>
#define INF 1<<29
#define SET(a, x) memset((a), (x), sizeof(a))
#define i64 long long
#define pb push_back
#define EPS 1e-9
using namespace std;

struct node
{
    int cnt;
    int A[4];
}X[2500009];
int id,ans,len,nw,i,j;
char str[52];



void insert()
{
    len=strlen(str),j;
    nw=0;
    for(i=0;i<len;i++)
    {
        //j=getid(str[i]);
        if(str[i]=='A')j=0;
        else if(str[i]=='C')j=1;
        else if(str[i]=='G')j=2;
        else if(str[i]=='T')j=3;

        if(X[nw].A[j]==-1)X[nw].A[j]=++id;
        nw=X[nw].A[j];
        X[nw].cnt++;
        ans=max(ans,X[nw].cnt*(i+1));
    }
}

int main()
{
    //filer();
    int i,j,k ,T,cas=0,n;
    //scanf("%d%d",,&N,&T);
    scanf("%d",&T);
    while(T--)
    {
        id=0;
        ans=0;
        n;
        for(i=0;i<=2500000;i++)
        {
            X[i].cnt=0;
            X[i].A[0]=-1;
            X[i].A[1]=-1;
            X[i].A[2]=-1;
            X[i].A[3]=-1;
        }
        scanf("%d",&n);
        for(i=0;i<n;i++)
        {
            scanf("%s",str);
            insert();
        }
        printf("Case %d: %d\n",++cas,ans);
    }
    return 0;
}