using System;
using System.Collections.Generic;

namespace AtCoder0106_4
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] input = Console.ReadLine().Split(' ');
            int n = int.Parse(input[0]);
            int h = int.Parse(input[1]);
            List<int> a = new List<int>();
            List<int> b = new List<int>();
            int maxa = 0;

            for (int i = 0; i < n; i++)
            {
                string[] ken = Console.ReadLine().Split(' ');
                a.Add(int.Parse(ken[0]));
                b.Add(int.Parse(ken[1]));
                if (maxa < int.Parse(ken[0]))
                {
                    maxa = int.Parse(ken[0]);
                }
            }

            int nokorih = h;
            int num = 0;
            for (int i = 0; i < n; i++){
                if(nokorih < 0){
                    break;
                }
                if(maxa < b[i]){
                    nokorih -= b[i];
                    num++;
                }
            }

            if(nokorih < 0){
                // do nothing
            }else if(nokorih%maxa == 0){
                num += nokorih / maxa;
            }else{
                num += nokorih / maxa + 1;
            }

            Console.WriteLine(num);
        }
    }
}
