import math

n,h=map(int,input().split())
b=[]
max=1
for i in range(n):
    x,y=map(int,input().split())
    b.append(y)
    if max<x:
        max=x
for z in b:
    if z<max:
        b.remove(z)
b.sort()
b.reverse()
sum=0
ans=0
for x in b:
    sum+=x
    ans+=1
    if sum>=h:
        print(ans)
        break
if sum<h:
    ans+=math.ceil((h-sum)/max)
    print(ans)