from math import ceil
n,h=map(int,input().split())
a=[0]*n
b=[0]*n
for i in range(n):
  a[i],b[i]=map(int,input().split())
dmax=max(a)
b.sort(reverse=True)
ans=0
for d in b:
  if d<dmax:
    break
  h-=d
  ans+=1
print(ans+ceil(h/dmax))