#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("%11d",totalcost);
    }
    return 0;
}