Excel Range value lookup and assign

Dear Team,
File1.xls (113.5 KB)
File2.xlsx (12.4 KB)

DSOTest.xaml (11.4 KB)

The existing developer has made the attached process based on excel file1.

Now there file format has changed instead to create new code i would like to change the assign activity based on attached file2.

Please look into Assign activity need to be change based on file2. Am getting an error " Get Range Total: Conversion from string “C32” to type ‘Integer’ is not valid." in “Get Range Total” Assign activity.