MDr,s=MBASEr,s*(1+(PRIr,s,t−1*EXRATEr−MPRICr,sMPRICr,s*𝐞𝐥𝐚𝐬𝐭𝐫𝐩𝐫s))elmpr1*(1+(PRIr,s,t−1*EXRATEr−MPRICr,sMPRICr,s−PRIr,s,t−2*EXRATEr,t−1−MPRICr,s,t−1MPRICr,s,t−1*𝐞𝐥𝐚𝐬𝐭𝐫𝐩𝐫s))elmpr2