#coding: UTF-8

import sys
import re
import itertools
from collections import deque

### defs ###
def swap(x,y):
	x = x^y
	y = x^y
	x = x^y
	return (x,y)

def count(xa,ya,d):
	x1=xa[0]; x2=xa[1];
	y1=ya[0]; y2=ya[1];
	res=0

	x = x2-x1
	y = y2-y1
	d = d - x1 - y1
	if (d < 0):
		return 0

	if(x>y):
		x,y=swap(x,y)

	if (0 <= d and d <= x):
		res = (d+2)*(d+1)//2
	elif (x<=d and d<=y):
		res = (d+2)*(d+1)//2 - (d-x)*(d-x+1)//2
	elif (y<=d and d<=x+y):
		res = (x+1)*(y+1) - (x+y-d)*(x+y-d+1)//2
	elif (x+y <= d):
		res = (x+1)*(y+1)

	return res
	
### main ###
x1,y1,x2,y2,d = map(int, sys.stdin.readline().split())

if (x1>=0):
	xs = [[x1,x2]]
elif (x2<=0):
	xs = [[-x2,-x1]]
else:
	xs = [[1,-x1],[0,x2]]

if (y1>=0):
	ys = [[y1,y2]]
elif (y2<=0):
	ys = [[-y2,-y1]]
else:
	ys = [[1,-y1],[0,y2]] 

ans = 0
for xarea in xs:
	for yarea in ys:
		ans += count(xarea,yarea,d)

print(int(ans))