#include<stdio.h>
int main(){
    int qualityX, priceX, qualityY, priceY, qualityZ, priceZ, total;
    scanf("%d %d", &qualityX,&priceX);
    scanf("%d %d", &qualityY,&priceY);
    scanf("%d %d", &qualityZ,&priceZ);
    if(qualityX<0 || priceX<0 || qualityY<0 || priceY<0 ||qualtityZ<0)
    print("Invalid input");
    else{
    tota=((qualityX*priceX)+(qualityY*priceY)+(qualityZ*priceZ));
    printf("%d",total);
    }
    return 0;
}