#!/usr/bin/env python3
def f(x, y, d): # [0, x) * [0, y)
    assert 0 <= x
    assert 0 <= y
    d = min(d, x + y - 2)
    ans = (d+1)*(d+2)//2
    if x < d:
        dx = d-x+1
        ans -= dx*(dx+1)//2
    if y < d:
        dy = d-y+1
        ans -= dy*(dy+1)//2
    return ans
x1, y1, x2, y2, d = map(int,input().split())
assert x1 < x2
assert y1 < y2
if x2 <= 0:
    x1, x2 = - x2, - x1
if y2 <= 0:
    y1, y2 = - y2, - y1
if x1 <= 0:
    x1, y1 = y1, x1
    x2, y2 = y2, x2
ans = 0
if x1 <= 0:
    assert x1 <= 0 <= x2
    assert y1 <= 0 <= y2
    ans += f(abs(x1),   abs(y1),   d)
    ans += f(abs(x1),   abs(y2)+1, d)
    ans += f(abs(x2)+1, abs(y1),   d)
    ans += f(abs(x2)+1, abs(y2)+1, d)
elif y1 <= 0:
    assert 0 <= x1 < x2
    assert y1 <= 0 <= y2
    ans -= f(x1,   abs(y1),   d)
    ans += f(x2+1, abs(y1),   d)
    ans -= f(x1,   abs(y2)+1, d)
    ans += f(x2+1, abs(y2)+1, d)
    ans -= x2-x1+1
else:
    assert 0 <= x1 < x2
    assert 0 <= y1 < y2
    ans += f(x1,   y1,   d)
    ans -= f(x1,   y2+1, d)
    ans -= f(x2+1, y1,   d)
    ans += f(x2+1, y2+1, d)
print(ans)