#include <stdio.h>
int main() {
    int q1, p1, q2, p2, q3, p3;
    if (scanf("%d %d" , &q1, &p1) !=2 ||
         scanf("%d %d", &q2, &p2) !=2 || 
         scanf("%d %d ", &q3, &p3) !=2) { 
         printf("Invalid input\n");
         return 0;
} 
   if ( q1 < 0 || P1 < 0 || q2 < 0 || p2 < 0 || q3 < 0 || p3 < 0) {
    printf("Invalid input\n");
} else { 
    int total = q1 * p1 + q2 * P2 + q3 *p3;
    printf("%d\n", total);
}
return 0;
}