#include<stdio.h>
#include<algorithm>
using namespace std;
int ABS(int a){return max(a,-a);}
int main(){
	int a,b,c,d,e;scanf("%d%d%d%d%d",&a,&b,&c,&d,&e);
	for(int i=0;i<20;i++){
	int ab=0;
	if((long long)a*c>0)ab=min(ABS(a),ABS(c));
	int bb=0;
	if((long long)b*d>0)bb=min(ABS(b),ABS(d));
	
	a=max(a,-e+bb);
	b=max(b,-e+ab);
	c=min(c,e-bb);
	d=min(d,e-ab);
	//printf("%d %d %d %d\n",a,b,c,d);
	if(a>c||b>d){
		printf("0\n");return 0;
	}
	
	}
	long long ret=(long long)(c-a+1)*(d-b+1);
	if(ABS(a)+ABS(b)>e){
		int r=ABS(a)+ABS(b)-e;
		ret-=(long long)r*(r+1)/2;
	}
	if(ABS(a)+ABS(d)>e){
		int r=ABS(a)+ABS(d)-e;
		ret-=(long long)r*(r+1)/2;
	}
	if(ABS(c)+ABS(b)>e){
		int r=ABS(c)+ABS(b)-e;
		ret-=(long long)r*(r+1)/2;
	}
	if(ABS(c)+ABS(d)>e){
		int r=ABS(c)+ABS(d)-e;
		ret-=(long long)r*(r+1)/2;
	}
	
	printf("%lld\n",ret);
}