using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace atcoder_b_085
{
    class _04
    {
        static void Main()
        {

            int N;
            int H;
            int count = 0;

            string[] str = Console.ReadLine().Split(' ');
            N = int.Parse(str[0]);
            H = int.Parse(str[1]);

            int[] a = new int[N];
            int[] b = new int[N];

            for(int i = 0; i < N; i++)
            {
                str = Console.ReadLine().Split(' ');
                a[i] = int.Parse(str[0]);
                b[i] = int.Parse(str[1]);
            }

            Array.Sort(a);
            Array.Reverse(a);
          

            for(int i = 0; i < N; i++)
            {
                if(a[0] < b[i])
                {
                    H += -b[i];
                    count++;
                    if (H <= 0)
                    {
                        Console.WriteLine(count.ToString());
                        return;
                    }
                }
            }

            for(int i=0; H > 0; i++)
            {
                H += -a[0];
                count++;
            }

            Console.WriteLine(count.ToString());

        }
    }
}
