#! /usr/bin/env python
# -*- coding: utf-8 -*- #

def Usa_Cipher_Dec(s):
    strlist = list(s)
    dec = ''
    for i, c in enumerate(strlist):
        dec += chr((ord(c) - ord('A') - (i+1)) % 26 + ord('A'))
    return dec

S = raw_input()
ans = Usa_Cipher_Dec(S)

print ans