<?while($a=fgets(STDIN)){if($a[0]=='L')$s=8;if($a[0]=='U')$s=14;if($a[0]=='G')$s=20;for($i=0;$i<strlen($a);$i++){$c=ord($a[$i]);if($c>96||($c>64&&$c<91)){$c+=$s;if($c>122||($c>90&&$c<91+$s))$c-=26;}echo(chr($c));}}
Note that non-ascii characters in the above source code will be escaped (such as \x9f).