The roof has a slope of 5/12. According to code, when 3-tab asphalt shingles are being installed in an area where ice dams form an approved membrane shall extend from the eave to how far inside the exterior wall line?

The roof has a slope of 5/12. According to code, when 3-tab asphalt shingles are being installed in an area where ice dams form an approved membrane shall extend from the eave to how far inside the exterior wall line?