<?php
list($vege, $meat, $double, $count) = explode(" ",trim(fgets(STDIN)));
for($i = 1; $i <= $vege; $i++){
    if($meat - ($i * $double) >= 0){
        if($count - ($i + ($i * $double)) >= 0){
            $ans = $i;
        } else {
            $ans = 0;
        }
    } else {
        $ans = 0;
    }
}
echo $ans;