# -*- coding: utf-8 -*-
"""
Created on Wed Jun 20 16:39:29 2018

@author: Yuya
"""



N, H = map(int, input().split())

A_max = 0
D_seq = []

for i in range(N):
    A, D = map(int, input().split())
    if A>A_max:
        A_max = A
    D_seq.append(D)

D_sum = 0
D_count = 0
D_seq.sort()

for i in range(N):
    if D_seq[i] > A_max and D_sum < H:
        D_sum += D_seq[i]
        D_count += 1

A_sum = H-D_sum

if A_sum > 0:
    if A_sum%A_max == 0:
        print(A_sum//A_max + D_count)
    else:
        print(A_sum//A_max + D_count+1)
else:
    print(D_count)
