##18.rb
a = ('A'..'Z').to_a
ll = gets.chomp.split("").map(&:to_s)
r = []

Array(ll).each_with_index do |l,i|
  if a.index(l) - i - 1 >= 0
    r.push(a[a.index(l) - i - 1])
  else
  	rp = i / a.length
  	r.push(a[a.index(l) - i + rp * a.length - 1])
  end
end
print r.join.to_s