#include <stdio.h>
int main() {
  int qx, px, qy, py, qz, pz;
    if(scanf("%d %d %d %d %d %d",&qx ,&px ,&qy, &py ,&qz ,&pz) != 6){
        printf("Invalid input\\n");}
        return 0;
    if(qx < 0 || px < 0 || qy < 0 || py < 0 || qz < 0 || pz < 0) {
        printf("Invalid input\\n");}
        return 0;
   total = (long long)qx * px + (long long)qy * py + (long long)qz * pz;
    printf("%11d\n",total);
    return 0;
}