kesalahan tidak bisa menambah user

Kesalahan Detailnya :

1.) Pemberitahuan : Objek kelas mysqli_result tidak dapat diubah menjadi int di C: \ xampp \ htdocs \ inventory \ users.php pada baris 202

2.) Kesalahan fatal : Kesalahan Jenis Tidak Tertangkap: mysqli_num_rows (): Argumen # 1 ($ result) harus bertipe mysqli_result , bool diberikan di C: \ xampp \ htdocs \ inventory \ users.php: 202 Pelacakan tumpukan: # 0 C: \ xampp \ htdocs \ inventory \ users.php (202): mysqli_num_rows (true) # 1 {main} dimasukkan C: \ xampp \ htdocs \ inventory \ users.php di baris 202

Code Line 202:

if (mysqli_num_rows($cek > 0))

Full Code :

<?php
if (isset($_POST['submit'])) {
	$nama = $_POST['nama'];
	$level = $_POST['level'];
	$username = $_POST['username'];
	$password = $_POST['password'];

	$cek = mysqli_query($connect, "SELECT * FROM user WHERE username = '$username'");
	if (mysqli_num_rows($cek > 0)) {
		$_SESSION['danger'] = "Maaf, username tersebut sudah ada, mohon coba lagi";
	}
	else {
		$query = mysqli_query($connect, "
		INSERT INTO user(nama, username, password, level)
		VALUES ('$nama', '$username', MD5('$password'), '$level') ")OR DIE(mysqli_error($connect));
		if ($query) {
			$_SESSION['success'] = "Data berhasil dimasukkan";
			echo "<script>location.replace('users.php');</script>";
		}
		else {
			$_SESSION['danger'] = "Error saat memasukkan data";
		}
	}
}

?>