[EpiData-list] Conditional formula

Hello Epidata users, I am having problem to code conditional formula in epidata as described below, can anyone suggest how to code to the following condition,

If a= 1 and b = 1 then exposure= K

If a= 1 and b = 0 then exposure= K

If a= 1 and b = 1 and c= 1 then exposure= K

If a= 1 and b = 1 and c= 1 and d=0 then exposure= K

If a= 1 and b = 1 and c= 1 and d=1 then exposure= K

else exposure= K1

Thanks