The required SN of an asphalt pavement to protect the roadbed soil is 5.1. The required SN to protect the sub-base material is 3.1. The required structural number for the base material is 2.3.The layer structural coefficients for sand sub-base, crushed stone base and asphalt concrete are 0.12, 0.15, and 0.42. The drainage coefficients for the sub-base and base are 0.8 and 0.9 respectively.What are the required thicknesses of the layers