<?php
//  T2exs15ti23ng1_3cT1h3e0_Roppe
$input = readline();
$number = [];
$noNumber = [];
$take = [];
$skip = [];
$result = "";
for ($i = 0; $i < strlen($input); $i++) {
    if (ctype_digit($input[$i])) {
        $number [] = $input[$i];
    } else {
        $noNumber[] = $input[$i];
    }
}
for ($i = 0; $i < count($number); $i++) {
    if ($i % 2 == 0) {
        $take[] = $number[$i];
    } else {
        $skip[] = $number[$i];
    }
}
$indexSkip = 0;
for ($i = 0; $i < count($take); $i++) {

}