Bulls vs Cows is also known as MasterMind. The game generates a secret four digit number. All four digits are different. The number will not begin with 0. The goal of the game is to guess the secret number with the fewest possible attempts. If a digit you guess is present in the secret number, but is not in the correct place, it is a "cow". If the guessed digit is present in the secret number and is also in the correct place, it is a "bull".

For example:
The generated secret number is 1234. The first attempt to guess the number was 1749. The result of this first attempt will be one "bull" and a one "cow". Digits 1 and 4 are included in this secret number. The number 1 is in the correct place and the number 4 is not.

Good luck!