Application for android, sharpened by instagram.

Hello! It is necessary to make an application for android, sharpened by instagram (without api). An application with the ability to unsubscribe from the people the user is following. There are a lot of the same applications, but you need to make such an application that will work as quickly as possible with a minimum load and not crash - these are very important points. The task of the application is simple: The user logs in to the application by entering his username and password. After which he can choose several actions: 1. Manual unsubscribing from those to whom it is subscribed. It works like this: the user goes into this section, sees all the people he is subscribed to and can manually unsubscribe from them. 2. Automatic unsubscribe. It works like this: the user goes into this section, clicks "automatic unsubscribe" and the application unsubscribes from all people with whom there is no mutual subscription ie each person from the subscriptions is being checked whether he is subscribed to the user. If not signed, the application unsubscribes from it. It's all. Interested in the cost and timing of implementation. I repeat that to work without api since such an application does not approve instagram. It is necessary to make authorization through the browser. Either an imitation of a browser, or based on a free browser (both easier and cheaper). Thank you for the attention.