Server

import socket
from random import random as rand

def b(mystring):
    return bytes(mystring, 'utf-8')
def bc(mystring):
    return mystring.decode('utf-8')

sock = socket.socket()
sock.bind(('', 9090))
sock.listen(0)

conn, addr = sock.accept()

while True:
    data = bc(conn.recv(1024))
    if not data:
        break
    elif data=="S":conn.send(rand())