n,h=map(int,input().split())
a,b=[0]*n,[0]*n
for i in range(n):
    a[i],b[i]=map(int,input().split())
p=max(a)
b.sort(reverse=True)
ans=0
for i in range(n):
    if b[i]>=p:
        ans+=1
        h-=b[i]
        if h<=0:
            print(ans)
            exit()
x=(-h//p)*(-1)
ans+=x
print(ans)
