n, h = gets.split.map(&:to_i)
Ary = readlines.map(&:chomp!).map { |e| e.split.map(&:to_i) }
Ary.sort_by!{ |e| e[1] }
huri_max = Ary.max_by { |e| e[0] }

count = 0
while h >= 0 do
  nage_max = Ary.last

  if Ary.size > 1 && nage_max[1] > huri_max[0]
    h -= nage_max[1]
    Ary.pop
    count += 1
    next
  else
    h -= huri_max[1]
    count += 1

    count += h / huri_max[0]
    count += 1 if h % huri_max[0] != 0

    break
  end
end

puts count
