I have a column A1:A17 which displays variations the following data.

5f
6f
7f
1m
1m 1f
1m 2f
1m 3f
1m 4f
1m 5f
1m 6f
1m 7f
2m
2m 1f
2m 2f
2m 3f
2m 4f
2m 5f

The data refers to race distances.

As 1m (mile) = 8f (furlongs), how can I simplify the data to show the
following data in B1:B17?

5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21

I was using the ISERROR function, but that does not work anymore, maybe
because of formatting?