How to set Estimated maximum daily cost in Google adwords api Traffic Estimator Service in php

I want to get Traffic estimation for some keywords via Google Adwords api.

So I'm using the api : https://developers.google.com/adwords/api/docs/guides/traffic-estimator-service

Here there's a option to set maximum amount for CPC per day :

$money = new Money(); $money->setMicroAmount(5000000); $adGroupEstimateRequest->setMaxCpc($money); /* Here they're setting Max cpc value per day */ 

But i want to Set Maximum daily budget for the keyword. Anyways to make it possible please share your ideas.