Impossible challenge question.

Question

There's a challenge question to complete the blanks to make a function that returns $x to the power of $y.

<?php
function p($x,$y){
$res=_;
for($i=1;$i<___;$i++){
$res_=$x;
}
return $res;
}
?>

The only working solution I find is
$x
$y
*

but the first answer space only allows 1 character. The second blank requires 3. The third allows one. I don't see how that's possible.

<?php
function p($x,$y){
$res=$x;
for($i=1;$i<$y;$i++){
$res*=$x;
}
return $res;
}
echo p(10,100);
?>

Answer 1

<?php
function p($x,$y){
$res=1;
for($i=1;$i<=$y;$i++){
$res*=$x;
}
return $res;
}
?>

is the answer.