Cow&Bull

You have just to guess the chosen number by the smart phone to win. Rules:

• All figures in the secret number are different.
• The secret number can start with zero.
• If in your proposal you have numbers that figures in the secret number in the right places, they are bulls.
• If in your proposal you have numbers that figures in the secret number, but not in the right places, they are cows. You can choose how many digits will be the secret number but it will be more difficult, by default with 4 digits.