thanks guys for your sugesstions.

I already have a job offer here is US but I recently got my canadian PR so I must land to canada before end of June. I did not want to give up my canadian PR but I am not planning to go move there right away. but I do not have valid visa. I need to get visa stamps in Canada. my questions is, should I go to canada while I am still on F1 visa or after I graduate. I am graduating in May. My OPT starts in June.

thanks guys