Use command "python main.py" to run the program, and follow the instructions.

"RSA key pair generation" function:
The "keygen.txt" file contains n, e, d.
The "secret.txt" file contains p, q.

"encryption" function
it will open a file called "encrypt.txt", which contains n, e, text.
it will print cipher text on screen.

"decryption" function:
it will open a file called "decrypt.txt", which contains n, d, cipher.
it will print plain text on screen.

The codes quoted in "main.py" are used to generate "encrypt.txt" and "decrypt.txt" automatically.