{-# OPTIONS_GHC -O3 #-}
{-# LANGUAGE ViewPatterns, ScopedTypeVariables #-}

import qualified Data.ByteString as B (getLine)
import qualified Data.ByteString.Char8 as C (readInt, words, unpack, reverse, dropWhile)
import qualified Data.Maybe as M (fromJust)
import Data.Char as C (isSpace)

rstrip = C.reverse . C.dropWhile C.isSpace . C.reverse

main = do
    (C.unpack . rstrip -> xxs) <- B.getLine
    putStrLn $ [x | (xi, x) <- (zip [1..] xxs), xi `mod` 2 == 1]
