integer::i
  character*1024::code,decode
  read *, code
  do i=1, LEN_TRIM(code)
     decode(i:i) = CHAR(MOD(ICHAR(code(i:i))-ICHAR('A')-i+2600,26)+ICHAR('A'))
  end do
  print '(a)', decode(1:LEN_TRIM(code))
end program