RewriteEngine On

RewriteRule ^([^/]+)$                 o.php?isim=$1                    [QSA,L]
RewriteRule ^([^/]+)/$                 o.php?isim=$1                    [QSA,L]
RewriteRule ^([^/]+)/([^/]+)/([^/]+)/?$ o.php?isim=$1&isim2=$2&isim3=$3 [QSA,L]