<?php

function generateOTP() {
    return 'P' . str_pad(strval(random_int(0, 999999)), 6, "0", STR_PAD_LEFT);
}
$otp=generateOTP();

$input=empty("");

if($otp==$input){
echo "true\n";
}

else
{
echo "false\n";
}

echo $otp;
echo gettype($otp); //otp는 string임

?>