#!/usr/local/bin/ruby

m, c = 0, 0

while c < 30 do
  m += 1
  c += 1 if m % 4 == 0
  c += 1 if m % 9 == 0
  # puts "#{m} -> #{c}"
end

puts m

mm, cc = 0, 30


def test(cus, min)
  inc_min = min + 1
  minas = [inc_min % 4, inc_min % 9].count {|r| r == 0}

  return inc_min if cus - minas <= 0 
  test(cus - minas, inc_min)
end
puts test(30, 0)