How to Hide Backup by Supsystic Admin Menus

function plt_hide_backup_by_supsystic_menus() {
	//Hide "Backup by Supsystic".
	remove_menu_page('supsystic-backup');
	//Hide "Backup by Supsystic → Backup by Supsystic".
	remove_submenu_page('supsystic-backup', 'supsystic-backup');
	//Hide "Backup by Supsystic → Overview".
	remove_submenu_page('supsystic-backup', 'admin.php?page=supsystic-backup&tab=overview');
	//Hide "Backup by Supsystic → Backup".
	remove_submenu_page('supsystic-backup', 'supsystic-backup');
	//Hide "Backup by Supsystic → Schedule".
	remove_submenu_page('supsystic-backup', 'admin.php?page=supsystic-backup&tab=bupSchedule');
	//Hide "Backup by Supsystic → Restore".
	remove_submenu_page('supsystic-backup', 'admin.php?page=supsystic-backup&tab=bupLog');
	//Hide "Backup by Supsystic → Migration".
	remove_submenu_page('supsystic-backup', 'admin.php?page=supsystic-backup&tab=migration');
	//Hide "Backup by Supsystic → Featured Plugins".
	remove_submenu_page('supsystic-backup', 'admin.php?page=supsystic-backup&tab=featured-plugins');
}

add_action('admin_menu', 'plt_hide_backup_by_supsystic_menus', 11);

Where do I put this code?