#include<stdio.h>
#define max(a,b) a>b?a:b
int main(){
	int a,b,c,d,e,v1,v2,aa,bb,cc;
	while(scanf("%d%d%d%d%d",&a,&b,&c,&d,&e)!=EOF){
		aa=a-2*e;
 	    bb=b-2*e;
		cc=c-2*e;
		if(d<e){
	    	v1=a*b*c-2*d*(aa*bb+aa*cc+bb*cc);
	    	printf("%d\n",v1);
		}
		if(d>=e){
			v1=8*e*e*e+4*e*e*(aa+bb+cc);
			v2=(a-2*d)*(b-2*d)*(c-2*d);
			printf("%d\n",max(v1,v2));
		}
    }
}