list($max_yasai, $max_niku, $c, $total) = explode(" ", trim(fgets(STDIN)));

$sub_total = 0;

for ($yasai=0; $yasai <= $max_yasai; $yasai++) 
{
    $niku = $yasai*$c;
    $sub_total = $yasai + $niku;
    
    // 肉が在庫を超えないとき
    if ($niku <= $max_niku) {
        if ($sub_total < $total) $today_yasai = $yasai;
    }
    
}
    
echo $today_yasai."\n";