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

count = 0
Ary.each do |katana|
  if katana[1] > huri_max[0]
    h -= katana[1]
    count += 1
    if h <= 0
      puts count
      exit
    end
  end
end

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

puts count
