proc `%%`(a, b: int): int = result = ((a mod b) + b) mod b

var
  s = stdin.readLine
  n = len(s)
  res = ""

for i, ch in s:
  var nch = (ch.ord - 'A'.ord - i - 1) %% 26
  nch += 'A'.ord
  res.add(nch.chr)

echo res