<?php
$teststring="αβγδεζηθΙκΛμ";
if (!preg_match("/^[A-ZA-zΑ-Ωα-ωίϊΐόάέύϋΰήώ0-9\- ]+$/", $teststring)) { echo "invalid char";
}
else {
echo "success";
}
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