using System;

class MainClass
{
    public static void Main(string[] args)
    {
        string[] s = Console.ReadLine().Split(' ');
        int N = int.Parse(s[0]);
        long H = long.Parse(s[1]);
        long a = -1;
        long[] b = new long[N];
        long sum = 0;

        for (int j = 0; j < N; j++)
        {
            string[] s1 = Console.ReadLine().Split(' ');
            long aa = long.Parse(s1[0]);
            if (aa > a) a = aa;

            b[j] = long.Parse(s1[1]);

        }

        Array.Sort(b);
        Array.Reverse(b);
        int i = 0;

        while (H > 0)
        {


            if (a >= b[i])
            {
                if (H <= a)
                {
                    sum++;
                    Console.WriteLine(sum);
                    return;
                }
                else
                {
                    sum += H / a;
                    if (H % a > 0) sum++;
                    Console.WriteLine(sum);
                    return;
                }
            }
            else
            {
                H -= b[i];
                i++;
            }
            sum++;
        }

        Console.WriteLine(sum);
    }
}