How to get the route length in kilometers Yandex Maps?

Question

JavaScript

Greetings, I'm trying to deal with yandex api, I need to get the distance in kilometers between two points on the map. I deduced the route between these points using a simple example from the documentation

var multiRoute = new ymaps.multiRouter.MultiRoute({
        referencePoints: [
            "Санкт-Петербург",
            "Москва"
        ],
        // Параметры маршрутизации.
        params: {
            results: 2
        }
    }, {
        boundsAutoApply: true
    });

But I don't understand how to get the distance between them for further calculations.
Need your help gentlemen