func main()
	var S: []char :: cui@input()
	for i(0, ^S - 1)
		var n: int :: S[i] $ int - 'A' $ int - (i + 1)
		do n :% 26
		do n :+ n < 0 ?(26, 0)
		do S[i] :: 'A'.offset(n)
	end for
	var ans: []char :: S
	do cui@print("\{ans}\n")
end func