#nullable enable

using System.Numerics;

void Run()
{
    var n = Int();
    var s = new HashSet<string>();
    for (var i = 0; i < n; i++)
    {
        var b = String() + " " + String();
        if (s.Contains(b))
        {
            Out("Yes");
            return;
        }
        s.Add(b);
    }
    Out("No");
}

#region
var _io_ = new AtCoderIO(){ Backend = new() };
Run();
_io_.Backend.Flush();

string String() => _io_.Next();
int Int() => int.Parse(String());
void Out(object? x, string? sep = null) => _io_.Out(x, sep);

class AtCoderIO
{
    public required StandardIOBackend Backend { get; init; }

    ReadOnlyMemory<string> _input = Array.Empty<string>();
    int _iter = 0;
    public string Next()
    {
        while (_iter >= _input.Length) (_input, _iter) = (Backend.ReadLine().Split(' '), 0);
        return _input.Span[_iter++];
    }

    public void Out(object? x, string? separator = null)
    {
        if (x == null) return;
        separator ??= Environment.NewLine;
        if (x is System.Collections.IEnumerable a and not string)
        {
            var objects = a.Cast<object>();
            if (separator == Environment.NewLine && !objects.Any()) return;
            x = string.Join(separator, objects);
        }
        Backend.WriteLine(x);
    }
}

class StandardIOBackend
{
    readonly StreamReader _sr = new(Console.OpenStandardInput());
    readonly StreamWriter _sw = new(Console.OpenStandardOutput()) { AutoFlush = false };
    public string ReadLine() => _sr.ReadLine()!;
    public void WriteLine(object? value) => _sw.WriteLine(value);
    public void Flush() => _sw.Flush();
}
#endregion

static class Extensions
{
    public static T[] Repeat<T>(this int time, Func<T> F) => Enumerable.Range(0, time).Select(_ => F()).ToArray();

    public static int ToFlag(this int i)
    {
        if (i < 0 || 31 <= i) throw new IndexOutOfRangeException();
        return 1 << i;
    }
    public static bool OfFlag(this int value, int i) => (value & ToFlag(i)) > 0;
    public static int WithFlag(this int value, int i, bool f) => f ? (value | ToFlag(i)) : (value & ~ToFlag(i));

}