python3, 100 bytes

Result

AC

Duration

553ms

Code [DL]

print(''.join([chr(ord(x)+i+1 if ord(x)+i+1<91 else ord(x)+i+1-26) for i, x in enumerate(input())]))

stdin

KVTBEWUWVKKBOUWSQUSERRIXYO

stdout

LXWFJCBEEUVNBILIHMLYMNFVXO

stderr

strace