You could do something like this. Formula in F5 for this example.

=MID(E5,1,1)&"-"&MID(E5,2,100)

I used 100 in this formula because I would not think what you are working
with would be longer than that. But if it is then just increase the number.

If you want to be more technical you could do ths instead of using 100:

=MID(E5,1,1)&"-"&MID(E5,2,LEN(E5)-1)

Then you can copy it down. Then do a Copy / Paste Special - Value to change
the formual to a value.

Hope this help.

Steven