#-*- coding: utf-8 -*-

def decodechar(c, i):
	n = ord(c) - 65
	newn = (n - i - 1) % 26
	newc = chr(newn+65)
	return newc

s = raw_input()
ans = ""
for i in range(0, len(s)):
	ans = ans + decodechar(s[i], i)

print ans