Given a random key K of length m bits. K is used as a one time$-$pad to encrypt plaintext message P$1($of length m bits$)$ to obtain ciphertext C$1.$ K is then also used to encrypt plaintext P$2($of length m bits$)$ to obtain ciphertext C$2($i$.$e$.,$ the key is reused!$).$ If the adversary is able to obtain C$1,$ C$2,$ and P$2($known plaintext attack$),$ explain how he can compute P$1$