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();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var c = NList;
        var (n, w) = (c[0], c[1]);
        var ans = -1;
        for (var i = 0; i < n; ++i)
        {
            c = NList;
            if (c[1] <= w) ans = Math.Max(ans, c[0]);
        }
        WriteLine(ans);
    }
}