while s = gets do
  26.times do
    break if s.include?("the") || s.include?("this") || s.include?("that")
    s.length.times do |i|
      s[i] = (s[i].ord + 1).chr if s[i] != '.' && s[i] != ' '
      s[i] = 'a' if s[i] > 'z'
    end
  end
  puts s
end