How to Hide GPTranslate Admin Menus

function plt_hide_gptranslate_menus() {
	//Hide "GPTranslate".
	remove_menu_page('gptranslate');
	//Hide "GPTranslate → Translations".
	remove_submenu_page('gptranslate', 'gptranslate');
	//Hide "GPTranslate → Settings".
	remove_submenu_page('gptranslate', 'gptranslate-settings');
	//Hide "GPTranslate → Wizard".
	remove_submenu_page('gptranslate', 'gptranslate-wizard');
}

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

Where do I put this code?