// CECR 2012
// Problem E: Word Equations
// Correct solution, O(kp)
// Author: Jakub Pachocki

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

class Solver {
	
	int position;

	void dfs(String symbol, Map<String, String[]> grammar, String pattern, Set<String> visited) {
		if (visited.contains(symbol)) {
			return;
		}
		visited.add(symbol);
		if (grammar.get(symbol).length == 1) {
			String word = grammar.get(symbol)[0];
			for (int i = 0; i < word.length() && position < pattern.length(); ++i) {
				if (word.charAt(i) == pattern.charAt(position)) {
					++position;
					visited.clear();
				}
			}
		} else {
			dfs(grammar.get(symbol)[0], grammar, pattern, visited);
			dfs(grammar.get(symbol)[1], grammar, pattern, visited);
		}
	}
	
	void solve() throws IOException {
		Reader.init(System.in);
		int nCases = Reader.nextInt();
		for (int testCase = 0; testCase < nCases; ++testCase) {
			Map<String, String[]> grammar = new HashMap<String, String[]>();
			int n = Reader.nextInt();
			for (int i = 0; i < n; ++i) {
				String symbol = Reader.next();
				Reader.next();
				String original = Reader.next();
				if (original.charAt(0) < 'a') {
					Reader.next();
					grammar.put(symbol, new String[]{original, Reader.next()}); 
				} else {
					grammar.put(symbol, new String[]{original});
				}
			}
			String startSymbol = Reader.next();
			String pattern = Reader.next();
			Set<String> visited = new HashSet<String>();
			position = 0;
			dfs(startSymbol, grammar, pattern, visited);
			System.out.println(position == pattern.length() ? "YES" : "NO");
		}
	}
}

public class E {

	public static void main(String[] args) throws IOException {
		(new Solver()).solve();
	}

}

/** Class for buffered reading int and double values */
class Reader {
    static BufferedReader reader;
    static StringTokenizer tokenizer;

    /** call this method to initialize reader for InputStream */
    static void init(InputStream input) {
        reader = new BufferedReader(
                     new InputStreamReader(input) );
        tokenizer = new StringTokenizer("");
    }

    /** get next word */
    static String next() throws IOException {
        while ( ! tokenizer.hasMoreTokens() ) {
            //TODO add check for eof if necessary
            tokenizer = new StringTokenizer(
                   reader.readLine() );
        }
        return tokenizer.nextToken();
    }

    static int nextInt() throws IOException {
        return Integer.parseInt( next() );
    }
	
    static double nextDouble() throws IOException {
        return Double.parseDouble( next() );
    }
}