<?php

[$z,$y,$x] = explode(" ",trim(fgets(STDIN)));
$ans = 0;

if ($y >= $z && ($y - $z) >= $x) {
    $ans += $z;
    $ans += $x;
}elseif ($y < $z && ($z - $y) >= $x) {
    $ans += $y;
    $ans += $x;
}elseif ($y >= $z && ($y - $z) < $x) {
    $ans += $z;
    $ans += ($y -$z + $x)/2;
}else {
    $ans += $y;
    $ans += ($z - $y + $x)/2;
}


echo $ans;