input = gets
output = ""
alphabet = ('A'.ord..'Z'.ord).to_a.map(&:to_i).map(&:chr)
gap = 1
input.split(//).each_with_index{|val, index|
  if index < input.length - 1 then
    output << alphabet[(val.ord - 65 - gap) % 26].to_s
  end
  gap+=1
}
puts output