#nullable enable

#region
var _input = Array.Empty<string>();
var _iter = 0;
string String()
{
    while (_iter >= _input.Length) (_input, _iter) = (Console.ReadLine()!.Trim().Split(' '), 0);
    return _input[_iter++];
}
T I<T>() where T : IParsable<T> => T.Parse(String(), null);
#endregion

T[] Range<T>(int n, Func<T> F) => Enumerable.Range(0, n).Select(_ => F()).ToArray();

bool Solve()
{
    var n = I<int>();
    var byMax = 0;
    var bxMin = int.MaxValue;
    var queries = Range(n, () => (String(), String()));
    foreach (var (x, y) in queries)
    {
        if (x == "a")
        {
            if (y.Contains('a')) return true;
            else byMax = Math.Max(byMax, y.Length);
        }
        if (!x.Contains('a')) bxMin = Math.Min(bxMin, x.Length);
    }
    return bxMin <= byMax;
}

string Run() => Solve() ? "Yes" : "No";

string Join<T>(IEnumerable<T> values, bool ws = false) => string.Join(ws ? " " : Environment.NewLine, values);
Console.WriteLine(Join(Range(I<int>(), Run)));