
s=raw_input().split(' ')
n=int(s[0])
h=int(s[1])

mx=0
ar=[]
for i in range(n):
	s=raw_input().split(' ')
	a=int(s[0])
	b=int(s[1])
	if a>mx:
		mx=a;
	ar.append(b)

v=0
s=0
ar.sort(reverse=True)
for i in range(len(ar)):
	if ar[i]>mx:
		h=h-ar[i]
		v=v+1
	else:
		break;
	if h<=0:
		break;

if h>0:
	if h%mx==0:
		v=v+(h/mx)
	else:
		v=v+(h/mx)+1

print(v)