[power-pro] How to use for...endfor to calculate 5x4x3x2x1

[Wai]

I write the following script to calculate 5x4x3x2x1, but the result is 
wrong.What wrong?

Local v r
r=1
For (v=5;v=1;v=v-1)
        r = r*v
EndFor

win.debug(r)