Lay the foundation-one month.
Then repair each floor for 7 days, about 1 month.
Build the top of the stairs for another five days.
Building wall and plastering, 1 month.
Of course, this is not calculated according to your two or four people, but according to the type of work and the complete staffing. If it is two or four people, it is estimated that it will take a month to repair a floor, and it may not be finished. Everyone is exhausted. You see, lifting steel bars, blanking, forming, binding, moving templates, cutting, installing boards, cement, sand, stones, scaffolding, installing small lifting equipment and so on.