#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <vector>
#include <queue>
#include <cstring>
#include <string>
#include <algorithm>
using namespace std;
typedef  long long  ll;
typedef unsigned long long ull;
#define MM(a,b) memset(a,b,sizeof(a));
#define inf 0x7f7f7f7f
#define FOR(i,n) for(int i=1;i<=n;i++)
#define CT continue;
#define PF printf
#define SC scanf
const int mod=1000000007;
const int N=505+10;
ull seed=13331;
ull num[N];
int a[N];
char s[505][2005];

bool inter(int id,int k)
{
    int len=strlen(s[id]);
    ull tmp=0,big=0,base=1;

    for(int i=0;i<len;i++)
        {
            tmp=tmp*seed+s[id][i];
            big=big*seed+s[k][i];
        }
    for(int i=0;i<len-1;i++) base*=seed;
    if(tmp==big) return true;
    for(int i=len;s[k][i]!=‘\0‘;i++)
    {
        big=(big-s[k][i-len]*base)*seed+s[k][i];
        if(big==tmp) return true;
    }
    return false;
}

int main()
{
    int cas,n,kk=0;scanf("%d",&cas);
    while(cas--){
        scanf("%d",&n);
        int pos=0,ans=-1;
        for(int i=1;i<=n;i++)
        {
            scanf("%s",s[i]);
            while(1)
            {
                if(!pos) {a[++pos]=i;break;}
                if(inter(a[pos],i)) pos--;
                else
                 {
                     a[++pos]=i;
                     ans=i;
                     break;
                 }
            }
        }
        printf("Case #%d: %d\n",++kk,ans);
    }
    return 0;
}