If I already had a Debug class in the main namespace. What will be the output of the following code?

If I already had a Debug class in the main namespace. What will be the output of the following code?

namespace main;
use com\getinstance\util\Debug;
<pre lang="php" cssfile="hk1_style" >
class Debug {
    static function helloWorld() {
        print "hello from main\Debug";
    } 
}
 
Debug::helloWorld();