#include <iostream>
#include <algorithm>
#include <cstring>
#include <string>
#include <vector>
#include <cmath>
#include <sstream>
#include <queue>
 
using namespace std;
typedef long long ll; typedef vector<int> VI;
typedef pair<int,int> pii;
 
#define rep2(x,fr,to) for(int (x)=(fr);(x)<(to);(x)++)
#define rep(x,to) for(int (x)=0;(x)<(to);(x)++)
#define repr(x,fr,to) for(int (x)=(fr);(x)>=(to);(x)--)
#define all(c) (c).begin(),(c).end()
#define sz(v) (int)(v).size()
 
#define debug(X) cout<<"["<<#X<<"]"<<X<<endl;
#define debug2(X) cout<<X<<endl;

#define MAX_N 2010
#define MAX_M 3

const int INF=1e8;
typedef pair<int,int>P;

//int dx[4]={1,0,-1,0},dy[4]={0,1,0,-1};
//	queue<P> que;
int a[4],k,L,H,d;

#include <deque>
int main(){
cin >>a[0]>>a[1]>>a[2]>>a[3]>>d;

int minT,maxT;
 minT=min(abs(a[0]),abs(a[2]))+min(abs(a[1]),abs(a[3]));
 //maxT=max(abs(a[0]),abs(a[2]))+max(abs(a[1]),abs(a[3]))-minT;
 k=d-minT;
 L=min((a[2]-a[0]),(a[3]-a[1]));
 H=max((a[2]-a[0]),(a[3]-a[1]));

 if (k<0){cout <<0<<endl;}
 else if (L+H<k){cout <<(H+1)*(L+1)<<endl;}
 else if (0<=k && k<L){cout <<(k+1)*(k+2)/2<<endl;}
 else if (L<=k&& k<=H){cout <<L*(L+1)/2+(L+1)*(k-L+1)<<endl;}
 else if (H<k && k<=L+H){cout <<(H+1)*(L+1)-(L+H-k)*(L+H-k+1)/2<<endl;}

}