Open Safe

Open Safe:
To open a safe you should guess a four-digit code in a given number of tries.
In the Beginners level after each try digits will change color to:
Red – if the digit is not used in this combination.
Yellow – if the digit is in the code, but in a different position.
Green – if the digit is in the correct position.
In Expert level after each try you will get:
Green number – indicates how many digits are in the right position,
Yellow number - indicates how many digits are used in the code, but in a different position.