#ifdef LOCAL111
#else
	#define NDEBUG
#endif
#include <bits/stdc++.h>
const int INF = 1e9;
using namespace std;
template<typename T, typename U> ostream& operator<< (ostream& os, const pair<T,U>& p) { cout << '(' << p.first << ' ' << p.second << ')'; return os; }

#define endl '\n'
#define ALL(a)  (a).begin(),(a).end()
#define SZ(a) int((a).size())
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define RFOR(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define REP(i,n)  FOR(i,0,n)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)
#define RBP(i,a) for(auto& i : a)
#ifdef LOCAL111
	#define DEBUG(x) cout<<#x<<": "<<(x)<<endl
	template<typename T> void dpite(T a, T b){ for(T ite = a; ite != b; ite++) cout << (ite == a ? "" : " ") << *ite; cout << endl;}
#else
	#define DEBUG(x) true
	template<typename T> void dpite(T a, T b){ return; }
#endif
#define F first
#define S second
#define SNP string::npos
#define WRC(hoge) cout << "Case #" << (hoge)+1 << ": "
#define rangej(a,b,c) ((a) <= (c) and (c) < (b))
#define rrangej(b,c) rangej(0,b,c)
template<typename T> void pite(T a, T b){ for(T ite = a; ite != b; ite++) cout << (ite == a ? "" : " ") << *ite; cout << endl;}
template<typename T> bool chmax(T& a, T b){if(a < b){a = b; return true;} return false;}
template<typename T> bool chmin(T& a, T b){if(a > b){a = b; return true;} return false;}

typedef long long int LL;
typedef unsigned long long ULL;
typedef pair<int,int> P;
typedef pair<LL,LL> LP;

void ios_init(){
	//cout.setf(ios::fixed);
	//cout.precision(12);
#ifdef LOCAL111
	return;
#endif
	ios::sync_with_stdio(false); cin.tie(0);	
}

int main()
{
	ios_init();
	LL x1, y1, x2, y2, d;
	while(cin >> x1 >> y1 >> x2 >> y2 >> d){
		// swap(y1,y2);
		LL ans = 0;
		FOR(i,x1,x2+1){
			if(0 <= i and i <= d){
				ans += max((min(y2,d-i)-max(y1,-(d-i)))+1,0LL);
			} else if (-d <= i and i < 0){
				ans += max(min(y2,(d+i))-max(y1,-(d+i))+1,0LL);
			}
			// DEBUG(ans);
		}
		cout << ans << endl;
	}
	return 0;
}