Q$3$: Consider the following table, which uses a Caesar cipher with a key of $20$ to encode the plaintext message "networks". Each plaintext letter is converted to its corresponding numerical value $($A$=0,$ B$=1,...,$ Z$=25).$ Using the key K$=20$K $=20$K$=20,$ the cipher formula C$=($P$+$K$)$ mod$26$C $=($P $+$ K$)\backslash$mod $26$C$=($P$+$K$)$mod$26$ is applied to get the ciphertext value, which is then converted back to a letter. Fill in the missing values in the table and explain the process in detail for each step.