using System.Numerics;

public class Program
{
    public static void Main()
    {

        //BigInteger num = BigInteger.Parse(Console.ReadLine() ?? string.Empty);
        int num = int.Parse(Console.ReadLine() ?? string.Empty);
        //string[] moji = (Console.ReadLine() ?? string.Empty).Trim().Split(' ');
        //string str = Console.ReadLine() ?? string.Empty;


        List<int> list = new List<int>();
        List<int> result = new List<int>();
        for(int i = 0; i < num; i++)
        {
            string[] moji = (Console.ReadLine() ?? string.Empty).Trim().Split(' ');
            list.Add(int.Parse(moji[0]));
            result.Add(int.Parse(moji[1]));
        }

        for(int i = 0;i < list.Count;i++)
        {
            int month= list.LastIndexOf(list[i]);
            if(month == i)
            {
                continue;
            }
            int day = result.LastIndexOf(result[i]);
            if(day == i)
            {
                continue;
            }
            Console.WriteLine("Yes");
            return;
        }
        Console.WriteLine("No");

    }

}