#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;
}