How to Hide Availability datepicker - InputWP Admin Menus

function plt_hide_date_time_picker_field_menus() {
	//Hide the "InputWP" menu.
	remove_menu_page('dtpicker');
	//Hide the "InputWP → Settings" menu.
	remove_submenu_page('dtpicker', 'dtpicker');
	//Hide the "InputWP → Integration" menu.
	remove_submenu_page('dtpicker', 'dtp_integration');
}

add_action('admin_menu', 'plt_hide_date_time_picker_field_menus', 1000000000);

Where do I put this code?