#include<stdio.h>
int main()
{
    int qx, px, qy, qz, pz, total;
    scanf("%d %d", &qx, &px);
    scanf("%d %d", &qy, &py);
    scanf("%d %d", &qz, &pz);
    if(qx < 0 || px < 0 || qy < 0 || py < 0 || qz < 0 || pz < 0 )
    priintf("Invalid input");
    else
    {
        total = (qx*px) + (qy*py) + (qz*pz);
        printf("%d", total);
   }
   return 0;
}