using System;
using System.Linq;

namespace ABC085_D
{
    class Program
    {
        static void Main(string[] args)
        {
            var NH = Console.ReadLine().Split().Select(int.Parse).ToArray();
            var N = NH[0];
            var H = NH[1];
            var k = new int[N][];
            var a = new int[N];
            var b = new int[N];

            for (int i = 0; i < N; i++)
            {
                k[i] = Console.ReadLine().Split().Select(int.Parse).ToArray();
                a[i] = k[i][0];
                b[i] = k[i][1];
            }
            var ma = a.Max();
            var mb = b.Max();
            var cntb = b.Where(x => x > ma).Count();
            var sumb = b.Where(x => x > ma).Sum();

            if (ma > mb) Console.WriteLine(H / ma + (H % ma == 0 ? 0 : 1));
            else if (sumb >= H) Console.WriteLine(cntb);
            else Console.WriteLine((H - sumb) / ma + cntb + ((H - sumb) % ma == 0 ? 0 : 1));
        }
    }
}
