#!/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

def test(cus, min = 0)
  inc_min = min + 1
  res_cus = cus - [inc_min % 4, inc_min % 9].count(0)

  res_cus <= 0 ? inc_min : test(res_cus, inc_min)
end
puts test(30)