# https://atcoder.jp/contests/abc085/tasks/abc085_d

n, hp = gets.split.map(&:to_i)

swords = []

n.times { swords << gets.split.map(&:to_i) }

strongest_slash_damage = swords.sort_by{ |s| s[0] }.reverse[0][0]

res = 0

valid_throw_damages = swords.find_all { |s| s[1] >= strongest_slash_damage }.map { |s| s[1] }
sum_throw_damages = valid_throw_damages.inject(:+)

res = valid_throw_damages.size
hp -= sum_throw_damages

res += (hp.to_f / strongest_slash_damage).ceil

puts res