using System;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static void Main(string[] args)
    {
        string[] s = Console.ReadLine().Split(' ');
        long n = long.Parse(s[0]);
        long h = long.Parse(s[1]);
        long[,] ab = new long[n,2];
        long am = 0;
        long mm = 0;
        long c = 0;
        for(long i = 0; i < n; i++)
        {
            string[] j = Console.ReadLine().Split(' ');
            ab[i, 0] = long.Parse(j[0]);
            ab[i, 1] = long.Parse(j[1]);
            if(am < ab[i, 0])
            {
                am = ab[i, 0];
                mm = i;
            }
        }
        for(long i = 0; i < n; i++)
        {
            if(i == mm)
            {
                continue;
            }
            h = h - ab[i, 1];
            c++;
            if(h > 0)
            {
                Console.WriteLine(c);
                return;
            }
        }
        c += h / am;

        Console.WriteLine(c);
    }
}