N, H = gets.chomp.split.map(&:to_i)
cmd = Array.new(N*2).map{Array.new(2)}
N.times do |n|
  line = gets.chomp.split.map(&:to_i)
  cmd[n*2] = [line[0],0]
  cmd[n*2+1] = [line[1],1]
end
cmd.sort!.reverse!
turn = 0
fill = 1
hp = H
while !cmd.empty?
  cur = cmd.shift
  if cur[1] == 1
    hp -= cur[0]
    turn += 1
    next
  end
  fill = cur[0]
  break
end
print "#{turn+hp/fill+(hp%fill!=0 ? 1:0)}\n"