<?php
[$n,$k] = explode(" ",trim(fgets(STDIN)));
$count = 0;
$a = explode(" ",trim(fgets(STDIN)));

rsort($a);

for($i = 0;$k < $i;$i++){
    if($a[$i] > 0){
        $count += $a[$i];
    }
}

echo $count;
?>