Use Python code.

Suppose that Alice and Bob are engaged in key-exchange using the Diffie-Helmann algorithm. Alice uses a secret number a, and Bob uses a secret number b. Eve knows neither a nor b. Alice and Bob choose the prime p 503 and the fixed number 3 for their exchange; Eve knows both of these pieces of information. Alice then sends Bob % 503-141 and Bob sends Alice 3 % 503-268. This communication is done over a public channel, so Eve knows both of the above numbers. Both Alice and Bob can then compute the shared secret % 503 by exponentiation, using their secret numbers. You are Eve. Find their shared secret 3ab % 503 This problem demonstrates that Diffie-Helmann can be broken if the prime p is too small.)