Trying to discover a hidden 4-digit number
I got the following hints:
GUESS RESULT
+---------+-------+
| 1 2 3 4 �| B B ��|
+---------+-------+
| 5 6 7 8 �| B B ��|
+---------+-------+
| 8 6 9 0 �| B R ��|
+---------+-------+
B- One of the digits of this guess exists in the hidden number in THE SAME position.
R- One of the digits of this guess exists in the hidden number in ANOTHER position.
What is the number?