function convert($num,$base_in,$base_out)
{
for($num=chr(strlen($num)).$num;ord($num[0])>0;$num[0]=chr(ord($num[0])-1)){
 if(ord($num[ord($num[0])])<=ord('9')){
 $dec+=$num[ord($num[0])]*pow($base_in,strlen($num)-ord($num[0])-1);}
 else {$dec+=(10+ord($num[ord($num[0])])-ord('a'))*pow($base_in,strlen($num)-ord($num[0])-1);}}
$num=chr(round(log($dec)/log($base_out)-0.5,0));
for ($num.=chr(0);ord($num[1])<=ord($num[0]);$num[1]=chr(ord($num[1])+1)){
$base_in = floor($dec/pow($base_out,(ord($num[0])-ord($num[1]))));
$dec-=$base_in*pow($base_out,ord($num[0])-ord($num[1]));
if ($base_in<=9){
$num.=$base_in;}
else{$num.=chr($base_in+ord('a')-10);}}
return substr($num,2);
}