#! /usr/bin/env ruby

if ARGV.length != 1
        abort("Incorrect arguments - needs input file")
elsif not File.exist? (ARGV[0])
	abort("File #{ARGV[0]} did not exist")
end

file = ARGV[0]

lines = File.open(file, "r").each_line(chomp: true)

steps = lines.first.each_char.to_a

node_lines = lines.drop(1).to_a

#first_node, _ = node_lines[0].split("=")
#first_node.strip!

nodes = node_lines.map {|line| node, rest = line.split("="); left, right = rest.split(","); [node.strip, {"L" => left.strip[1..-1], "R" => right.strip[0..-2]}]}.to_h

cur_nodes = nodes.keys.filter {|v| v[-1] == "A"}

step_counts = cur_nodes.map do |cur_node| 
	step_count = 0
	step_cycle = steps.cycle
	while cur_node[-1] != "Z"
		step_count += 1
		cur_node = nodes[cur_node][step_cycle.next]
	end
	step_count
end
puts step_counts.reduce(1, :lcm)