#include<stdio.h>
#include<math.h>

int main(){
	int a,b,c,d,e;
	while(scanf("%d %d %d %d %d",&a,&b,&c,&d,&e) != EOF){
		int v1,v2,s;
		if(e > d){
			v1 = a*b*c - 2*d*((a-2*e)*(c-2*e) + (b-2*e)*(c-2*e) + (b-2*e)*(a-2*e));
			printf("%d\n",v1);
		}else {
			s = (a-2*d)*(b-2*d)*(c-2*d);
			v2 = e*e*(a-2*e)*4 + e*e*(b-2*e)*4 + e*e*c*4;
			if(s > v2){
				printf("%d\n",s);
			}else {
				printf("%d\n",v2);
			}
		}
	}
	return 0;
}