extract numbers from a cell, before a specific text

Thank you. Moo's formula seems to work a little better, though it's not applicable when I have 99cv or lower
For instance, sbehera's give a "#VALUE!" error when the cell contains just "170cv"

So let's say the formula should work in the following cases:

170cv xxxx
170cv
xxxx 170cv
xxxx 170cv xxxx
50cv xxxx
50cv
xxxx 50cv
xxxx 50cv xxxx

always extracting only the number before "cv"

Thanks again for your kind help!