# coding: utf_8
""" abc085d """

import math

n, h = map(int, input().split())
katanaA = []
katanaB = []
for i in range(n):
    a, b = map(int, input().split())
    katanaA.append(a)
    katanaB.append(b)

maxA = max(katanaA)
throwKatanaB = [k for k in katanaB if k > maxA]
count = 0
for t in throwKatanaB:
    h -= t
    count += 1
    if h <= 0:
        break
if h <= 0:
    print(count)
else:
    count += int(math.ceil(h / maxA))
    print(count)
