lines = ARGF.read.split "\n"
graph = Hash.new { |h, k| h[k] = [] }

# parse input and build graph
lines.each do |line|
  line.match /(\w+) to (\w+) = (\d+)/ do |m|
    graph[m[1]] << [m[2], m[3].to_i]
  end
end

puts graph.inspect