Getting Manager Name from SP.UserProfiles.PeopleManager REST API using Sharepoint Designer Workflow 2013

I want to get the Manager Name using Sharepoint UserProfile REST API in Sharepoint designer Workflow 2013 by using "Call Http Webservice" action with url http://<site_URL>/_api/SP.UserProfiles.PeopleManager/GetUserProfilePropertyFor(accountName=@v,propertyName='Manager')?@v='domain\username' and i am able to get the result in JSON format

{"d":{"GetUserProfilePropertyFor":"domain\username"}}.

But I am not able to read the output thro' Dictionary.

Pls let me know how to implement in Sharepoint designer workflow for reading Sharepoint UserProfile REST API JSON output.

Thanks

Rajkumar V