#!usr/bim/python
#! -*- coding: utf-8 -*-
import numpy as np

nh = raw_input()
nh = nh.split()
n,h = map(int,nh)

a = np.zeros(n,int)
b = np.zeros(n,int)

for i in range(n):
    line = raw_input()
    line = line.split()
    line = map(int,line)
    a[i] = line[0]
    b[i] = line[1]

ans = 0
while h > 0:
    #print a,b,ans,h,
    if np.max(b) > np.max(a):
        h -= np.max(b)
        ans += 1
        b[np.where(b==np.max(b))] = 0
        #print "nageru"
    else:
        ans += h / np.max(a)
        if not h % np.max(a) == 0:
            ans += 1
        h = 0
        #print "huru"

print ans
