#coding: utf-8

import numpy as np

H, W = list(map(int, input().split()))

h, w = list(map(int, input().split()))

goban = np.array([[1 for i in range(W)] for j in range(H)])

goban[:h :] = 0

goban[:, :w] = 0

print((np.sum(goban)))
H, W = list(map(int, input().split()))

h, w = list(map(int, input().split()))

print(((H-h) * (W-w)))
# coding: utf-8
import numpy as np

H, W = list(map(int, input().split()))
h, w = list(map(int, input().split()))
goban = np.array([[1 for i in range(W)] for j in range(H)])
goban[:h:] = 0
goban[:, :w] = 0
print((np.sum(goban)))

H, W = list(map(int, input().split()))
h, w = list(map(int, input().split()))
print(((H - h) * (W - w)))

-# coding: utf-8 -import numpy as np - -goban = np.array([[1 for i in range(W)] for j in range(H)]) -goban[:h:] = 0 -goban[:, :w] = 0 -print((np.sum(goban))) +print(((H - h) * (W - w)))