Roof live load

dear engineers 

i want to apply the load combination of  (1.2D + 1.0W + L + 0.5(Lr or S or R))  however , I don't have snow nor rain loads and the live loads at roof are the same as other lower floors taken as ( 2 KN / M2 )

so what would be my comb in this case or it is not applicable to my analysis?