Change row input!

Hi exceler's
Got a problem being trying to solve for the last few hours, which may or not use the OFFSET function:

The function has a input value to return a answer from a row of digits.
Simply the 'row input value' locates ref row (if 1, its 1 row up...) and then adds the right cell vaule.

rows = 1 input means use 1: row up, 2: use 2 rows up etc...

values anwers row
A1: B1: C1: D1:
8 0 Row 2
1 0
2 6
3 2
1 1
6 3
6 5
7 1
8 2
3 4

work sheet file