Created Unassigned: System.Exception: Syntax error [9393]

Hi,

I am using excel sheet to calculate values from user provided inputs and i am getting error on the cell containing following formula

```
IF(C2=1,VLOOKUP(D7,A15:D28,4),(IF(C2=2,VLOOKUP(D7,A33:D46,4),VLOOKUP(D7,F15:I28,4))))
```

On line:

```
lblResult.Text = worksheet.Cell("D8").Value;
```

Attached file is template excel file i am using to calculate results

Please help

Thanks in advance