n,h=map(int,input().split())
AB=[list(map(int,input().split())) for _ in range(n)]

attack=max(AB)[0]
AB=sorted(AB, reverse=True, key=lambda x:x[1])
cnt=0
for i,j in AB:
    if j>=attack:
        h -=j
        cnt +=1
    if h<=0:print(cnt);exit()

print(cnt+h//attack if h%attack==0 else cnt+h//attack+1)