N,H=map(int,input().split())
a=[]
b=[]
for i in range(N):
    c,d=map(int,input().split())
    a.append(c)
    b.append(d)

num=0
at=a[0]
for i in range(N):
    tmp=a[i]
    if tmp>at:
        at=tmp
        num=i
ans=0
for i in range(N):
    if i!=num:
        if at<b[i]:
            H-=b[i]
            ans+=1
    if H<=0:
        break
if H<=0:
    print(ans)
    exit()
ans+=min((H+at-1)//at,(H-b[num]+at-1)//at+1)
print(ans)