import sys
import math
n,h=map(int,input().split())
ab=[list(map(int,input().split())) for i in range(n)]
a=[ab[i][0] for i in range(n)]
A=max(a)
b=[ab[i][1] for i in range(n) if ab[i][1]>A]
b=sorted(b,reverse=True)
cnt=0
for i in b:
  h-=i
  cnt+=1
  if h<=0:
    print(cnt)
    sys.exit()
print(cnt+math.ceil(h/A))