Concurrent FTP Distributed Math Server

A server concurrently communicating with 7 clients . Features are file sending and receiving , and distributed mathematical operations

steps :

1. Start server.py in terminal
2. Open any number of client.py terminals (here I limit it to 7, change s.listen(7) in server.py to accomodate more)
3. In client window you will be given options :
   1. press 1 for mathematical operations
   2. press 2 for sending file
   3. press 3 for receiving file
   4. press 4 to quit