#include <string>
#include <vector>
#include <algorithm>
#include <numeric>
#include <set>
#include <map>
#include <queue>
#include <iostream>
#include <sstream>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstring>
#include <cctype>
#include <cassert>
#include <limits>
#include <functional>
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define rer(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i))
#define reu(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))
#if defined(_MSC_VER) || __cplusplus > 199711L
#define aut(r,v) auto r = (v)
#else
#define aut(r,v) __typeof(v) r = (v)
#endif
#define each(it,o) for(aut(it, (o).begin()); it != (o).end(); ++ it)
#define all(o) (o).begin(), (o).end()
#define pb(x) push_back(x)
#define mp(x,y) make_pair((x),(y))
#define mset(m,v) memset(m,v,sizeof(m))
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3fLL
using namespace std;
typedef vector<int> vi; typedef pair<int,int> pii; typedef vector<pair<int,int> > vpii; typedef long long ll;
template<typename T, typename U> inline void amin(T &x, U y) { if(y < x) x = y; }
template<typename T, typename U> inline void amax(T &x, U y) { if(x < y) x = y; }

int calc(int x, int y1, int y2, int d) {
	return max(0, min(y2, d - abs(x)) + 1 - max(y1, -d + abs(x)));
}

int main() {
	int x1; int y1; int x2; int y2, d;
	while(~scanf("%d%d%d%d%d", &x1, &y1, &x2, &y2, &d)) {
		//\sum_{x=x1}^x2 max(0,min(y2,d-abs(x))+1-max(y1,-d+abs(x)))
		vector<ll> points;
		points.push_back(0);
		points.push_back(x1);
		points.push_back(x2 + 1);
		for(ll p : {-1, 0, 1}) for(ll q : {-1, 0, 1}) for(ll r : {-1, 0, 1}) for(ll t : {0,1})
			points.push_back(y1 * p + y2 * q + d * r + t);
		sort(points.begin(), points.end());
		points.erase(unique(points.begin(), points.end()), points.end());
		ll ans = 0;
		rep(i, points.size() - 1) {
			ll L = points[i], R = points[i + 1];
			if(x2 < L || R <= x1) continue;
			ll valL = calc((int)L, y1, y2, d);
			if(L + 1 == R) {
				ans += valL;
				continue;
			}
			ll diff = calc((int)L + 1, y1, y2, d) - valL;
			ll width = R - L;
			ans += valL * width + diff * (width * (width-1) / 2);
		}
		printf("%lld\n", ans);
	}
	return 0;
}