I just did it , good news , even if you dont do exactly 2 years , it still counts . So the law is not only for 2 years and more staying before PR.refer this calculator
https://www.canadavisa.com/citizenship-wizard.html
Also even you do a vacations before PR , they dont reduce days number. Because in the calculator they didnt ask for vacations.
In the calculator , it is not allowed to do a futur PR date , so i did as i got my PR on may.