<?php

$hh = readline();
$mm = readline();

$sum = (($hh*60) + $mm + 15);
$resulthour = floor($sum / 60);
$resultmin = $sum % 60;
if ($resulthour > 23) {
    echo "0".":";
} else {
    echo $resulthour . ":";
}

if ($resultmin < 10) {
    echo "0";
}
echo $resultmin;