import sys
import math

n,h = map(int,input().split())
a = [0 for i in range(n)]
b = [0 for i in range(n)]
for i in range(n) :
  a[i],b[i] = map(int,input().split())
  
b.sort(reverse=True)

c = 0
for i in range(n) :
  if b[i] < max(a) :
    break
  h -= b[i]
  c += 1
  if h <= 0 :
    print(c)
    sys.exit()

print(c + math.ceil(h/max(a)))