<?php
$a = trim(fgets(STDIN));

$n =strpos($a,"pain");

$word1 = mb_substr($a,0,$n);

$count = substr_count($word1,"pon");

if($count == 2){
    echo 1;
}elseif($count > 2){
    echo $count - 1;
}else{
    echo -1;
}

?>