x1, y1, x2, y2, d = map(int, input().split())

dx = 0
dy = 0
m = float('inf')
for x, y in (x1, y1), (x1, y2), (x2, y1), (x2, y2):
    temp = abs(x)+abs(y)
    if temp <= m:
        dx = x
        dy = y
        m = temp

if x1 <= 0 <= x2 and y1 <= 0 <= y2:
    d_ = d+m
else:
    d_ = d-m

if d_ < 0:
    print(0)

X = max(abs(x2-dx), abs(x1-dx))
Y = max(abs(y2-dy), abs(y1-dy))
if Y > X:
    X, Y = Y, X
#print(dx, dy)
#print(X, Y)
if 0 <= d_ <= Y:
    ans = (d_+1)+d_*(d_+1)//2
elif Y < d_ <= X:
    ans = (Y+1)+Y*(Y+1)//2
    ans += (Y+1)*(d_-(Y+1)+1)
elif X < d_ <= X+Y:
    ans = (Y+1)+Y*(Y+1)//2
    ans += (Y+1)*(X-(Y+1)+1)
    ans += (X+Y+1)*(d_-(X+1)+1)
    ans -= (d_)*(d_+1)//2-X*(X+1)//2
else:
    ans = (Y+1)+Y*(Y+1)//2
    ans += (Y+1)*(X-(Y+1)+1)
    ans += (X+Y+1)*(X+Y-(X+1)+1)
    ans -= (X+Y)*(X+Y+1)//2-X*(X+1)//2
print(ans)