using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static string[] SList(long n) => Enumerable.Repeat(0, (int)n).Select(_ => ReadLine()).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var t = NN;
        var ans = new bool[t];
        for (var u = 0; u < t; ++u)
        {
            var n = NN;
            var s = SList(n);
            ans[u] = Inf(n, s);
        }
        WriteLine(string.Join("\n", ans.Select(f => f ? "Yes" : "No")));
    }
    static bool Inf(int n, string[] s)
    {
        var map = new string[n][];
        for (var i = 0; i < n; ++i) map[i] = s[i].Split();
        var flg = false;
        var maxlen = 0;
        for (var i = 0; i < n; ++i)
        {
            if (map[i][0] == "a")
            {
                if (map[i][1].Contains('a')) return true;
                maxlen = Math.Max(maxlen, map[i][1].Length);
                flg = true;
            }
        }
        if (!flg) return false;
        for (var i = 0; i < n; ++i)
        {
            if (!map[i][0].Contains('a') && map[i][0].Length <= maxlen) return true;
        }
        return false;
    }
}