Hi GSingh,

You could Use Column "B" JUST as your Input Column.
You could then Insert the Following Formula into Cell "C2" ...
=IF(OR(B1="",B1=0,B1)*IF(B2="",B2=0),C1,B2)
.... and Copy it Down.
Therefore Column "C" will be the Results Column you are After.

Hope this Helps.
All the Best.
Paul