#include <bits/stdc++.h>
using namespace std;
#define M1  1000000007
#define M 2038074743
long long int a[100005],d[100005],dp[100005];
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    long long int n,m,x=0,y=0,z,k=0,i,j=0,l,ans=0,q=1,r=1,t,ca;
    cin>>t;
    ca=t;
    while(t--)
    {
        unordered_map< int,int>ma;
        vector<int>v;
        cin>>n;
        string s,p;
        for(i=0;i<n;i++)
        {
            cin>>p;
            y=p.size();
            v.push_back(y);
            x=0,y=0;
            for(j=0;j<p.size();j++)
            {
                x=(x*401+p[j])%M;
                //y=(y*409+p[j])%M1;
            }
            ma[x]=1;
        }
        cin>>s;
        m=s.size();
        x=0,y=0;
        for(i=0;i<m;i++)
        {
            dp[i]=1e7;
            x=(x*401+s[i])%M;
            //y=(y*409+s[i])%M1;
           // e[i]=y;
            a[i]=x;
            if(i==0)d[i]=1;
            else d[i]=(d[i-1]*401)%M;
        }
        dp[m]=1e7;
        auto ip = std::unique(v.begin(), v.end());
        v.resize(std::distance(v.begin(), ip));
        sort(v.begin(),v.end());
        dp[0]=0;
        for(i=0;i<m;i++)
        {
            for(j=0;j<v.size();j++)
            {
                z=v[j];
               // cout<<z<<" "<<i<<endl;
                if(i+z>m)break;
                if(i==0)
                {
                    x=a[z-1];
                  //  y=e[z-1];
                }
                else
                {
                    x=(a[i+z-1]-a[i-1]*d[z])%M;
                    x=(x+M)%M;
                    //y=(e[i+z-1]-e[i-1]*f[z])%M1;
                   // y=(y+M1)%M1;
                }
                if(ma[x])
                {
                   dp[i+z]=min(dp[i+z],dp[i]+1);
                }
              //  cout<<x<<" "<<y<<" "<<i<<endl;

            }
        }
        //cout<<dp[0]<<" "<<dp[1]<<" "<<dp[2]<<" "<<dp[3]<<endl;
        cout<<"Case "<<ca-t<<": ";
        if(dp[m]==1e7)cout<<"impossible"<<endl;
        else cout<<dp[m]<<endl;

    }
    return 0;
}