#codng utf-8
import math
N,H=map(int,input().split())
A=[0]*N
B=[0]*N
for i in range(N):
    a,b=map(int,input().split())
    A[i]=a
    B[i]=b
A.sort(reverse=True)
B.sort(reverse=True)
flg=0
for i in range(N):
    if B[i]<A[0]:
        l=i
        flg=1
        break
ans=0
tmp=0
if flg==0:
    for i in range(N):
        ans+=1
        tmp+=B[i]
        if tmp>=H:
            break
    if tmp<H:
        ans+=math.ceil((H-tmp)/A[0])
else:
    for i in range(l-1):
        ans+=1
        tmp+=B[i]
        if tmp>=H:
            break
    if tmp<H:
        ans+=math.ceil((H-tmp)/A[0])
        
print(ans)