#include<stdio.h>
void main()
{
    int a,b,c,d,e,f,s1,s2,s3,o;
    scanf("%d %d",&a,&b);
    scanf("%d %d",&c,&d);
    scanf("%d %d",&e,&f);
    if(a<=0 || b<=0 || c<=0 || d<=0 || e<=0 || f<=0)
    {
        printf("Invalid input")
    }
    else
    {
        s1=a*b;
        s2=c*d;
        s3=e*f;
        o=s1+s2+s3;
        printf("%d",o);
    }
}