Instagram Bio Contain "snapchat" word Filter.

Hello,
Usually people at Instagram post their Snapchat Usernames in their profiles Bio.
Example: instagram.com/m_alobaiid/
What I have is A big list of Instagram profiles Usernames, In a textfile.
I want a program to check each profile and extract the Snapchat username from the Bio.
and save the Snapchat usernames in a textfile.
Features:
* Load Instagram profiles usernames. (InstagramUsernames.txt)
* Prasing Instagram bio looking for Snapchat Usernames. Example: instagram.com/m_alobaiid/
* Multithreaded. (superfast).
* I need to use Instagram API or private API.
* Output.txt file.
I need this to be coded in c# or c++ or c!