# solution

import io
import sys
import math

n,h,*l=map(int,open(0).read().split())

array=max(l[::2])

c=0;f=1

for b in sorted(l[1::2])[::-1]:
	if b>array:
		h-=b
		c+=1
		if h<1:
			f=0
			break
print(c+(~-h//array+1)*f)