Excel 2007 : calculate value based on multiple low, medium, high cells

I'm trying to figure out how to calculate a score based on whether or not the user entered an "x" in various cells. I've got 11 columns in my spreadsheet:

Column 1 represents a new feature the user wants

Columns 2 - 4 are used for indicating the significance as low, medium or high (user puts "x" in only one column).
Columns 5 - 7 are used for indicating the effort as low, medium or high (user puts "x" in only one column).
Columns 8 -10 are used for indicating the risk as low, medium or high (user puts "x" in only one column).

In Column 11, I want to calculate a score based on the low, medium and high entries where low = 1, medium = 2 and high = 3. The minimum calculated scored is 3 and the max is 9.

Suggestions?