Constant Sum Total Cannot be Larger than 100% and Equal to 0%

I have a constant sum question with 5 boxes, for the sake of explaining, let's call them Boxes A, B, C, D, and E.
The person filling out the survey cannot keep ALL the boxes at 0%, nor can the person put answers that total above 100%.
I have figured out the 100% part, but the 0% part is my issue.
Is there a way to validate this (which I'm currently doing with ensuring A, B, C, D, and E cannot be larger than 100%), or do I have to use JavaScript? If so, can someone help me with that?
Thank you!

NOTE: The person can put a 0% in the boxes, it just cannot TOTAL 0%.