require 'pp'

n, h = ARGF.gets.split(" ").map(&:to_i)

ai = []
bi = []
for _ in 0...n
  a, b = ARGF.gets.split(" ").map(&:to_i)
  ai << a
  bi << b
end

amax = ai.max

blarge = bi.select{|x| x>amax}
bcount = blarge.size
bsum = blarge.reduce(:+)

h2 = h - bsum


acount = h2/amax
acount+=1 if h2 % amax != 0 

count = acount + bcount
puts count
