copy and past rows on multiple sheets into master sheet

I have workbook named “CB”
There are three sheet named “as”; “bs” and “cs”
When I entered anything into sheet “bs” and “cs”, automatically generate cell value of col A by formulas.
I want – when formula generates cell values it automatically posted into col A of sheet “as”. Values only, not formulas.
I am very new to BVA
Thanks.