#include<stdio.h>
int main ()
{
    int a,b,c,d,e,f;
	int sum;
    scanf("%d %d %d %d %d %d",&a,&b,&c,&d,&e,&f);
	sum=a+f+b;
	sum*=sum;
	sum=sum-b*b-d*d-f*f;
	printf("%d",sum);
   
	
	return 0;

}