#include<stdio.h>
int main(){
    int qX,pX,qY,pY,qZ,pZ;
    long long totalcost;
    if(scanf("%d %d",&qX ,&pX) != 2) return 1;
    if(scanf("%d %d",&qY ,&pY) != 2) return 1;
    if(scanf("%d %d",&qZ ,&pZ) != 2) return 1;
    if  (qX < 0 || pX < 0 || qY < 0 || pY < 0 || qZ < 0 || pZ < 0){
        printf("Invalid input");
    }else{
        totalCost = (long long)qX * pX + (long long)qY *pY + (long long)qZ * 
        printf("%lld",totalcost);
    }
    return 0;
}