#!/usr/bin/python3

def S(x):
    if x < 0:
        return 0

    a = x
    b = (x+1)
    if (a & 1) == 0:
        a >>= 1
    else:
        b >>= 1
    return (a)*(b)

def solve(x, y, dd):
    d = min(x+y,dd)
    return S(d+1) - (S(d-x) + S(d-y))

x1, y1, x2, y2, d = list(map(int, input().split()))
if x1 > 0:
    d -= x1;
    x2 -= x1;
    x1 = 0
if y1 > 0:
    d -= y1
    y2 -= y1
    y1 = 0
if x2 < 0:
    d += x2
    x1 -= x2;
    x2 = 0
if y2 < 0:
    d += y2
    y1 -= y2;
    y2 = 0

if d < 0:
    print(0)
    exit()

if d == 0:
    print(1)
    exit()

x1 = abs(x1)
x2 = abs(x2)
y1 = abs(y1)
y2 = abs(y2)

res = 0
res += (solve(x1,y1,d))
res += (solve(x1,y2,d))
res += (solve(x2,y1,d))
res += (solve(x2,y2,d))

x1 = min(d,abs(x1))
y1 = min(d,abs(y1))
x2 = min(d,abs(x2))
y2 = min(d,abs(y2))

res -= (x1+x2+y1+y2+3)
print(int(res))