n,h=map(int,input().split())
a=[];b=[]
for i in range(n):
  q,w=map(int,input().split())
  a+=[q]
  b+=[w]
m=max(a)
b.sort(reverse=True)
x=0
for i in b:
  h-=i
  x+=1
  if h<=0:
    break
if h>0:
  x+=-(-h//m)
print(x)