n,h=map(int,input().split())
ab=[list(map(int,input().split()))for _ in range(n)]
c=max([a[0] for a in ab])
d=[b[1] for b in ab if b[1]>c]
d.sort()
ans=0
while len(d)>0:
    h-=d.pop()
    ans+=1
    if h<=0:
        print(ans)
        exit()
f=(h+c-1)//c
print(ans+f)