import java.io.*;
import java.util.*;

/**
 *
 * @author Denis Tulskiy
 */
public class biomed {
    public static void main(String[] args) throws IOException{
        Scanner fi = new Scanner(new File("biomed.in"));
        int k = fi.nextInt();
		for (int kk = 0; kk < k; kk++) {
			int m = fi.nextInt();
			String s = fi.next();
			String[] ss = new String[200];
			for (int i = 0; i < m; i++) {
				ss[i] = fi.next();
			}

			int[] a = new int[1001];
			a[0] = 1;
			for (int i = 0; i < s.length(); i++) {
				for (int j = 0; j < m; j++) {
					if (s.startsWith(ss[j], i))
						if (a[i] != 0) {
							a[i + ss[j].length()] = a[i + ss[j].length()] == 0 ?
								(a[i] + 1) : (Math.min(a[i + ss[j].length()], a[i]+1));
						}
				}
			}

			System.out.println("Data Set " + (kk+1) + ":");
			int ans;
			if ((ans = a[s.length()] - 1) > 0)
				System.out.println(ans);
			else
				System.out.println("Impossible");
		}
    }
    
}