#include <bits/stdc++.h>
	using namespace std;

	int main() {
		int a,b,c,d,e;
		while(cin>>a>>b>>c>>d>>e){
			if(d<e){
				cout<<a*b*c-2*(a-2*e)*(c-2*e)*d-2*(b-2*e)*(c-2*e)*d-2*(b-2*e)*(a-2*e)*d<<endl;
			}
			else{
				int v1,v2;
				v1=e*e*e*8+e*e*((a-2*e)*4+(b-2*e)*4+(c-2*e)*4);
				v2=(a-2*d)*(c-2*d)*(b-2*d);
				cout<<max(v1,v2)<<endl;
			}
		}
	}