I have a column of values that look like: 00000000007310F0000

all cells are 19 chars in length, and the 15th char is alpha. I need to map
the 15th alpha char to a numeric. the mapping is as follows:

ABCDEFGHI (column F)
123456789 (column G)

this is where I'm at:
=REPLACE(C3,15,1,(IF(MID(C3,15,1)=({F3:F12}),({G3: G11}),"")))

please help