Below are a series of guesses for a 4-digit combination followed by hints. An "X" indicates that there is a correct digit in the correct place, and an "O" indicates that there is a correct digit out of its correct place. With these hints, try to deduce the correct 4-digit combination. All four digits will be between 1-9 and all will be different.
3 1 4 8 - X
7 2 5 1 - X
6 9 3 5 - OX
7 4 8 9 - OX
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