input = STDIN.read.chomp
columns = input
           .split("\n")
           .map{ |line| line.split("") }
           .transpose

part_1 = columns.map do |column|
  column
    .group_by(&:itself)
    .sort_by { |k, v| v.count }
    .last[0]
end.join

puts "Part 1: #{part_1}"

part_2 = columns.map do |column|
  column
    .group_by(&:itself)
    .sort_by { |k, v| v.count }
    .first[0]
end.join

puts "Part 2: #{part_2}"