#include<stdio.h>
int main()
{
	int a,b,c,d,e;
	int v;
	int v_1,v_2;
	while(scanf("%d %d %d %d %d",&a,&b,&c,&d,&e)!=EOF)
	{
		if(d<e)
		{
			v=a*b*c-2*(a-2*e)*(c-2*e)*d-2*(b-2*e)*(c-2*e)*d-2*(a-2*e)*(b-2*e)*d;
		}
		else if(2*d<b && 2*d<a && e<=2*d<c)
		{
			v_1=(a*c-(c-2*e)*(a-2*e))*e*2+e*e*(b-2*e)*4;
			v_2=(a-2*d)*(b-2*d)*(c-2*d);
			if(v_1>=v_2)
			{
				v=v_1;
			}
			else
			{
				v=v_2;
			}
		}
		else
		{
			v=(a*c-(c-2*e)*(a-2*e))*e*2+e*e*(b-2*e)*4;
		}
	printf("%d\n",v);
	}
	
}