Problem:
 Score : 100 points    Problem Statement There are H rows and W columns of white square cells.  You will choose h of the rows and w of the columns, and paint all of the cells contained in those rows or columns.  How many white cells will remain?  It can be proved that this count does not depend on what rows and columns are chosen.      Constraints  All values in input are integers.  1 \leq H, W \leq 20  1 \leq h \leq H  1 \leq w \leq W         Input Input is given from Standard Input in the following format:  H  W  h  w       Output Print the number of white cells that will remain.        Sample Input 1 3 2
2 1      Sample Output 1 1  There are 3 rows and 2 columns of cells. When two rows and one column are chosen and painted in black, there is always one white cell that remains.       Sample Input 2 5 5
2 3      Sample Output 2 6       Sample Input 3 2 4
2 4      Sample Output 3 0

Solution (Python):
N = list(map(int,input().split()))
n = list(map(int,input().split()))
print((N[0]-n[0])*(N[1]-n[1]))

Solution (Python):
H,W = map(int,input().split())
h,w = map(int,input().split())

print((H-h)*(W-w))

Solution (Python):
H,W = map(int,input().split())
h,w = map(int,input().split())

print(H*W-(h*W+(H-h)*w))

Solution (Python):
H, W  = map(int, input().split())
h, w  = map(int, input().split())
print(H*W-(h*W+w*H-h*w))

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

Solution (Python):
A,B = map(int,input().split())
C,D = map(int,input().split())
print((A-C)*(B-D))

Solution (Python):
H,W = map(int,input().split())
h,w = map(int,input().split())

ans = (H-h)*(W-w)
print(ans)

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())
ans = H * W - (h * W + w * H) + (h * w)
print(ans)

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())
print(H*W-(w*H + h*(W-w)))

Solution (Python):
def solve():
    H, W = map(int, input().split())
    h, w = map(int, input().split())

    ans = H*W - (((h*W)+(w*H)) - (h*w))
    print(ans)


if __name__ == '__main__':
    solve()

Solution (Python):
h,w=map(int,input().split())
a,b=map(int,input().split())
ans=((h*w)-(((a*w)+(b*h))-(a*b)))
print(ans)

Solution (Python):
a, b = map(int, input().split())
c, d = map(int, input().split())
print((a-c) * (b-d))

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

Solution (Python):
a,b=map(int,input().split())
h,w=map(int,input().split())
print(a*b-(h*b+w*a-h*w))

Solution (Python):
a,b=map(int,input().split())
c,d=map(int,input().split())
print((a-c)*(b-d))

Solution (Python):
h,w = map(int,input().split())
a,b = map(int,input().split())

print((h-a)*(w-b))

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())

print((H - h) * (W - w))

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

Solution (Python):
H,W = map(int, input().split())
h, w = map(int, input().split())
print(H * W - (h * W + w * H - h * w))

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

Solution (Python):
H, W = [int(x) for x in input().split()]
h, w = [int(x) for x in input().split()]
print((H-h)*(W-w))

Solution (Python):
h,w = map(int, input().split())
a,b = map(int, input().split())
print((h-a)*(w-b))

Solution (Python):

H, W = map(int, input().split())
h, w = map(int, input().split())

print((H-h) * (W-w))

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

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())

print((W-w) * (H -h))

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

Solution (Python):
h, w = [int(i) for i in input().split()]
ha, wa = [int(i) for i in input().split()]
print ((h - ha) * (w - wa))

Solution (Python):
import os, sys, re, math

(H, W) = [int(n) for n in input().split()]
(h, w) = [int(n) for n in input().split()]

print(H * W - (h * W + H * w - h * w))

Solution (Python):
H, W = [int(s) for s in input().split(' ')]
h, w = [int(s) for s in input().split(' ')]
print((H-h)*(W-w))

Solution (Python):
a, b = list(map(int, input().split(' ')))
c, d = list(map(int, input().split(' ')))
print((a-c) * (b-d))

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

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

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

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

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

Solution (Python):
a,b=map(int,input().split())
c,d=map(int,input().split())
print((a-c)*(b-d))

Solution (Python):
h,w = map(int, input().split())
h2,w2 = map(int, input().split())

print( (h - h2) * (w - w2))

Solution (Python):
from collections import Counter,defaultdict,deque
from heapq import heappop,heappush,heapify
import sys,bisect,math,itertools,fractions,pprint
sys.setrecursionlimit(10**8)
mod = 10**9+7
mod2 = 998244353
INF = float('inf')
def inp(): return int(sys.stdin.readline())
def inpl(): return list(map(int, sys.stdin.readline().split()))
def inpln(n): return list(int(sys.stdin.readline()) for i in range(n))

h,w = inpl()
a,b = inpl()
print(h*w-(a*w+h*b-a*b))

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

Solution (Python):
H, W = [int(x) for x in input().split()]
h, w = [int(x) for x in input().split()]
print((H-h)*(W-w))

Solution (Python):
H,W=map(int,input().split())
h,w=map(int,input().split())
print(H*W-h*W-w*H+h*w)

Solution (Python):
import numpy as np
print(np.prod(np.array(tuple(map(int, input().split()))) - np.array(tuple(map(int, input().split())))))

Solution (Python):
a,b = map(int, input().split())
a1,b1 = map(int, input().split())
print((a-a1)*(b-b1))

Solution (Python):
a,b=map(int,input().split())
c,d=map(int,input().split())
ans=a*b-b*c-a*d+c*d
print(ans)

Solution (Python):
H,W = map(int, input().split())
h,w = map(int, input().split())

print((H*W)-(h*W)-(H*w)+(h*w))

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

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

Solution (Python):
a,b=map(int,input().split())
c,d=map(int,input().split())
print((a-c)*(b-d))

Solution (Python):
H, W = map(int,input().split())
h, w = map(int,input().split())
ans = (H - h) * (W - w)
print(ans)

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())

print(H*W-(h*W+w*H-h*w))

Solution (Python):
h, w = [int(ip) for ip in input().split()]
y, x = [int(ip) for ip in input().split()]

count = w * h
delete = x * h + y * w
delete -= x * y

print(count - delete)

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())
s = H * W
s1 = h * W
s2 = H * w
s3 = s1 + s2 - h * w
print(s - s3)

Solution (Python):
h, w = map(int, input().split())
a, b = map(int, input().split())
lm = h * w
sm = (a * w + h * b) - a * b
print(int(lm - sm))

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

Solution (Python):
H,W = map(int,input().split())
h,w = map(int,input().split())
print(H*W-(h*W+H*w-h*w))

Solution (Python):
H,W = map(int,input().split())
h,w = map(int,input().split())
print(H*W-(h*W+H*w-h*w))

Solution (Python):
def p_a():
    H, W = map(int, input().split())
    h, w = map(int, input().split())
    print((H - h) * (W - w))
p_a()

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

Solution (Python):
a,b=map(int,input().split())
c,d=map(int,input().split())
print(a*b - (b*c + (a-c)*d) )

Solution (Python):
h,w = map(int,input().split())
a,b = map(int,input().split())
print((h-a)*(w-b))

Solution (Python):
h,w = map(int,input().split())
a,b = map(int,input().split())
print((h*w)-((a*w)+(b*h)-(a*b)))

Solution (Python):
H,W=map(int,input().split())
h,w=map(int,input().split())

print((H*W)-(H*w)-(W*h)+(h*w))

Solution (Python):
H, W = [int(i) for i in input().split()]
h, w = [int(i) for i in input().split()]
print((H - h) * (W - w))

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

Solution (Python):
H, W =map(int,input().split())
h, w =map(int,input().split())

T = H*W
nu = h*W+H*w-w*h
print(T-nu)

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())

print((H - h) * (W - w))

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())

a = H * W
b = h * W
c = w * (H - h)
d = a - (b + c)

print(d)

Solution (Python):
H,W = map(int,input().split())
h,w = map(int,input().split())

print(H*W-(h*W+H*w-h*w))

Solution (Python):
H,W=map(int,input().split())
h,w=map(int,input().split())

print((H-h)*(W-w))

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())

print((H * W) - (h * W + w * H - h * w))

Solution (Python):
h1,w1=map(int,input().split())
h2,w2=map(int,input().split())

print(h1*w1-(w1*h2+h1*w2-h2*w2))

Solution (Python):
H,W=map(int,input().split()) 
h,w=map(int,input().split()) 

ans=H*W-h*W-H*w+h*w

print(ans)

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())

print(H*W - H*w - W*h + h*w)

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

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())
print((H*W)-(h*W + w*H - h*w))

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())

ans = H*W - (H*w+W*h - h*w)
print(ans)

Solution (Python):
H,W=map(int,input().split())
h,w=map(int,input().split())

if H*W==h*w:
    print(0)
else:
    print(H*W-(h*W+w*H-w*h))

Solution (Python):
from sys import stdin
H, W = [int(x) for x in stdin.readline().rstrip().split()]
h, w = [int(x) for x in stdin.readline().rstrip().split()]
print((H * W) - (h * W) - (w * H) + (h * w))

Solution (Python):
H, W = map(int, input().split(" "))
h, w = map(int, input().split(" "))

print(H * W - h * W - w * H + h * w)

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())

print(H*W - (h*W + w*H - h*w))

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

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

Solution (Python):
import sys
input = sys.stdin.readline
def print_ans(H, W, h, w):
    """Test Case
    >>> print_ans(3, 2, 2, 1)
    1
    >>> print_ans(5, 5, 2, 3)
    6
    >>> print_ans(2, 4, 2, 4)
    0
    """
    print((H - h) * (W  -w))


if __name__ == '__main__':
    H, W = map(int, input().rstrip().split())
    h, w = map(int, input().rstrip().split())
    print_ans(H, W, h, w)

Solution (Python):
H,W=tuple(map(int,input().split()))
h,w=tuple(map(int,input().split()))
print((H-h)*(W-w))

Solution (Python):
H,W = map(int,input().split())
h,w = map(int,input().split())
S = H*W - h*W - H*w + h*w
print(S)

Solution (Python):
H,W=map(int, input().split())  
h,w=map(int, input().split())  

print(H*W - h*W - w*H + h*w)

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

Solution (Python):
H,W = map(int, input().split())
h,w = map(int, input().split())

ans=(H*W)-(h*W)-(w*H-h*w)
print(ans)

Solution (Python):
H,W = map(int,input().split(' '))
h,w = map(int,input().split(' '))
print(H*W - h*W - (w*H - h*w))

Solution (Python):

import math
import datetime




H, W = map(int, input().split())
hi, wi = map(int, input().split())

print ((H*W) - ((hi*W) + (wi*H) - (hi*wi)))

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())

HW = H * W
hW = h * W
Hw = H * w - h * w
print(HW - hW - Hw)

Solution (Python):
a,b=map(int,input().split())
c,d=map(int,input().split())
print ((a-c)*(b-d))

Solution (Python):
a, b = list(map(int, input().split()))
c, d = list(map(int, input().split()))
print((a - c) * (b - d))

Solution (Python):
def main():
    H, W = map(int, input().split())
    h, w = map(int, input().split())
    print(H * W - (W * h + (H - h) * w))


if __name__ == '__main__':
    main()

Solution (Python):
H,W = list(map(int, input().split()))
h,w = list(map(int, input().split()))

ans = (H-h)*(W-w)
print(ans)

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

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

Solution (Python):
H,W=map(int,input().split())
h,w=map(int,input().split())

print(H*W-H*w-h*W+h*w)

Solution (Python):
h1, w1 = map(int, input().split())
h2, w2 = map(int, input().split())
print((h1-h2)*(w1-w2))

Solution (Python):
H,W = map(int,input().split())
h,w = map(int,input().split())
print(H*W-(h*W+H*w-h*w))

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

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

Solution (Python):
H,W = map(int,input().split())
h,w = map(int,input().split())
print(H*W- h*W - w*H + h*w)

Solution (Python):
H,W=map(int,input().split(' '))
h,w=map(int,input().split(' '))

print((H-h)*(W-w))

Solution (Python):
H,W=map(int,input().split())
h,w=map(int,input().split())

H_h = H-h
W_w = W-w

print((H_h)*(W_w))

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

Solution (Python):
h, w=map(int, input().split())
H, W=map(int, input().split())

print((H-h)*(W-w))

Solution (Python):
H,W = (int(i) for i in input().split())
h,w = (int(i) for i in input().split())

ans = (H - h) * (W - w)
print(ans)

Solution (Python):
H,W = map(int,input().split())
h,w = map(int,input().split())

print((H-h)*(W-w))

Solution (Python):
H,W = map(int,input().split())
h,w = map(int,input().split())
a = (H-h)*(W-w)
print(a)

Solution (Python):
h,w=map(int, input().split())
H,W=map(int, input().split())
print(abs(h-H)*abs(w-W))

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())

print(H*W - h*W - H*w + w*h)

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

Solution (Python):
H,W=map(int,input().split()) 
h,w=map(int,input().split()) 

ans=H*W-h*W-H*w+h*w

print(ans)

Solution (Python):
H, W = map(int, input().split(' '))
h, w = map(int, input().split(' '))

print(H*W - (h*W + w*H - h*w))

Solution (Python):
h,w = map(int, input().split())
a,b = map(int, input().split())

print ((h-a) * (w-b))

Solution (Python):

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

Solution (Python):
H,W=map(int,input().split())
h,w=map(int,input().split())
zentai=H*W
answer=zentai-(h*W+H*w-h*w)
print(answer)

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

Solution (Python):
H,W = map(int,input().split())
h,w = map(int,input().split())
all = H*W
paint =h*W + w*H - h*w
print(all - paint)

Solution (Python):
data = list(map(int,input().split()))
data2 = list(map(int, input().split()))

print(data[0]*data[1]-data2[0]*data[1]-(data[0]-data2[0])*data2[1])

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

Solution (Python):
H, W = map(int, input().split());
h, w = map(int, input().split());
print((H-h)*(W-w))

Solution (Python):

import sys










def main():
    H, W, h, w = [int(x) for x in sys.stdin.read().split()]

    ans = H * W - (h * W + (H - h) * w)
    print(ans)



if __name__ == "__main__":
    main()

Solution (Python):
H,W = map(int,input().split(' '))
h,w = map(int,input().split(' '))

ans = H * W
ans1 = H*w
ans2 = W*h
ans = ans - (ans1 + ans2 - (w*h))
print(ans)

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())
a = H * W
b = h * w
c = h * W
d = H * w
e = c + d - b
f = a - e
print(f)

Solution (Python):
H,W=map(int,input().split())
h,w=map(int,input().split())
print((H*W)-(h*W)-(H*w)+(h*w))

Solution (Python):
H,W = map(int,input().split())
h,w = map(int,input().split())

print((H-h)*(W-w))

Solution (Python):
H , W = map(int , input().split())
h , w = map(int , input().split())

print((H-h)*(W-w))

Solution (Python):
H,W=map(int,input().split())
h,w=map(int,input().split())

print((H-h)*(W-w))

Solution (Python):
H,W=map(int, input().split()) 
h,w=map(int, input().split())
ans = (H-h)*(W-w)
if ans >=0:
    print(ans)
else:
    print(0)

Solution (Python):
H,W = map(int, input().split())
h,w = map(int, input().split())

ret = H*W - h*W-H*w + h*w

print(ret)

Solution (Python):
a,b = map(int,input().split())
c,d = map(int,input().split())

print( (a-c)*(b-d) )

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

Solution (Python):
H,W=[int(i) for i in input().split()]
h,w=[int(i) for i in input().split()]

if(h>=H or w>=W):
    print(0)
else:
    print((H-h)*(W-w))

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())

print((H-h)*(W-w))

Solution (Python):
H,W = map(int, input().split())
y,x = map(int, input().split())
print((H-y)*(W-x))

Solution (Python):
s=list(map(int,input().split()))
t=list(map(int,input().split()))
a=s[0]-t[0]
b=s[1]-t[1]
print(a*b)

Solution (Python):
def main():
    H,W = map(int,input().split())
    h,w = map(int,input().split())
    print(H*W-h*W-w*H+w*h)

if __name__ == '__main__':
    main()

Solution (Python):
a,b = list(map(int, input().split()))
line, row = list(map(int, input().split()))

print((a-line) * (b - row))

Solution (Python):
H, W = map(int, input().split())
h,w = map(int, input().split())

print(abs(H-h)*abs(W-w))

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

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())

print((H-h)*(W-w))

Solution (Python):

h_origin, w_origin = [int(s) for s in input().split()]
h, w = [int(s) for s in input().split()]
print((h_origin - h) * (w_origin - w))

Solution (Python):
h,w = map(int,input().split())
a,b = map(int,input().split())

print(h*w-(a*w+b*h-a*b))

Solution (Python):
a,b = map(int,input().split())
c,d = map(int,input().split())
print((a-c)*(b-d))

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

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

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

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

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

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

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

Solution (Python):
H, W = [int(i) for i in input().split()]
h, w = [int(i) for i in input().split()]
print(H * W - h * W - H * w + h * w)

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())

print(H * W - (h * W + w * H - h * w))

Solution (Python):
from sys import stdin

H,W = [int(x) for x in stdin.readline().rstrip().split()]
h,w = [int(x) for x in stdin.readline().rstrip().split()]

print(H*W-h*W-H*w+h*w)

Solution (Python):
HW = list(map(int, input().split()))
hw = list(map(int, input().split()))
print((HW[0] - hw[0]) * (HW[1] - hw[1]))

Solution (Python):
H,W=map(int,input().split())
h,w=map(int,input().split())
print(H*W-h*W-H*w+h*w)

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())

white = H * W
cross = h * w
black = h * W + H * w - cross

ans = white - black
print(ans)

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

Solution (Python):
h, w = map(int, input().split())
sh, sw = map(int, input().split())
ans = (h - sh) * (w - sw)
print(ans)

Solution (Python):
HW = input()
HW_ = HW.split()
H = int(HW_[0])
W = int(HW_[1])
hw = input()
hw_ = hw.split()
h = int(hw_[0])
w = int(hw_[1])

ans = H * W - (h * W + w * H - h * w)
print(ans)

Solution (Python):
H, W = list(map(int, input().split()))
h, w = list(map(int, input().split()))

print ( (H-h)*(W-w))

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())
ans = (H - h) * (W - w)
print(ans)

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

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

Solution (Python):
H,W = map(int,input().split())
h,w = map(int,input().split())
answer = 0
retu = H-h
tate = W-w

answer = retu * tate
print(answer)

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())

ans = H * W - h * W - H * w + h * w
print(ans)

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

Solution (Python):
h,w = map(int,input().split())
h1,w1 = map(int,input().split())
whole = h*w

print(whole - w*h1 - abs(h-h1)*w1)

Solution (Python):
H,W=[int(x) for x in input().split()]
h,w=[int(x) for x in input().split()]

ans = W*H - (W*h+H*w-w*h)
print(ans)

Solution (Python):
H,W=map(int,input().split())
h,w=map(int,input().split())

print(H*W-(h*W+H*w-h*w))

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())

print((H-h)*(W-w))

Solution (Python):
H,W = list(map(int,input().split()))
h,w = list(map(int,input().split()))

print((H-h)*(W-w))

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

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())

ans = H*W - h*W - H*w + h*w

print(ans)

Solution (Python):
H, W = [int(x) for x in input().split()]
h, w = [int(x) for x in input().split()]
print((H-h)*(W-w))

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())


print(H*W-(h*W+H*w-h*w))

Solution (Python):
H,W = map(int,input().split())
h,w = map(int,input().split())
print((H*W)-(h*W+(w*(H-h))))

Solution (Python):


def main():
    H, W = map(int, input().split())
    h, w = map(int, input().split())
    all_cells = H * W
    black_cells = h * W + w * H - (h * w)
    print(all_cells - black_cells)

if __name__ == "__main__":
    main()

Solution (Python):
H,W = map(int,input().split())
a,b = map(int,input().split())

white = (H * W) - (W * a) - ((H - a) * b)

print(white)

Solution (Python):
def main():
    H, W = map(int, input().split())
    h, w = map(int, input().split())
    print(H * W - (h * W + w * H - h * w))


if __name__ == "__main__":
    main()

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

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

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

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())

print((H-h)*(W-w))

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())

ans = (H - h) * (W - w)
print(ans)

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

Solution (Python):
H,W = list(map(int,input().strip().split()))
h,w = list(map(int,input().strip().split()))
all = H * W
minar = H * w + h * W - h * w
ans = all - minar
print(ans)

Solution (Python):
h , w = map(int,input().split())
h_0 , w_0 = map(int,input().split())

print((h - h_0) * (w - w_0))

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

Solution (Python):
H,W = map(int,input().split())
h,w = map(int,input().split())
a = H * W
x = W * h
y = (H - h) * w
print(a - (x + y))

Solution (Python):
H,W=map(int,input().split())
h,w=map(int,input().split())
print(H*W-(h*W+w*H)+h*w)

Solution (Python):
a, b=map(int, input().split())
h, w=map(int, input().split())
x=a*b
y=h*b
z=w*a
k=h*w
final=x-y-z+k
print(final)

Solution (Python):
H,W=map(int, input().split())
h,w=map(int, input().split())
ans=(W-w)*(H-h)
print(ans)

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

Solution (Python):
W,H=map(int,input().split())
w,h=map(int,input().split())
print(W*H-w*H-W*h+h*w)

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

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

Solution (Python):
a,b = map(int,input().split())
c,d = map(int,input().split())
print((a-c)*(b-d))

Solution (Python):
H, W = map(int, input().split())
h, w =  map(int, input().split())
print(H*W - h*W - H*w + h*w)

Solution (Python):
def slove():
    import sys
    input = sys.stdin.readline
    H, W = list(map(int, input().rstrip('\n').split()))
    h, w = list(map(int, input().rstrip('\n').split()))
    print((H - h) * (W - w))


if __name__ == '__main__':
    slove()

Solution (Python):
H,W=map(int,input().split())
h,w=map(int,input().split())
S=H*W
Hw=H*w
Wh=W*h
wh=w*h
print(S-Hw-Wh+wh)

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

Solution (Python):
H,W = map(int,input().split())
h,w = map(int,input().split())
ans = H * W
ans = ans - H * w -h * W
ans = ans + h * w
print(ans)

Solution (Python):
h, w = map(int, input().split())
a, b = map(int, input().split())

print(h*w - (h*b + w*a - a*b))

Solution (Python):
H , W = map(int,input().split())
h , w = map(int,input().split())

print(( H - h ) * (W - w))

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())
print(H*W -h*W-H*w+h*w)

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())

print((H - h) * (W - w))

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())

print(H*W-H*w-W*h+h*w)

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())
ans = H*W
if h*W<ans:
    ans -= h*W
    if (H-h)*w<ans:
        ans -= (H-h)*w
        print(ans)
    else:
        print(0)
else:
    print(0)

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

Solution (Python):
'''A - White Cells
https://atcoder.jp/contests/abc121/tasks/abc121_a

>>> main([3, 2], [2, 1])
1
>>> main([5, 5], [2, 3])
6
>>> main([2, 4], [2, 4])
0'''


def main(amount, portion):
    print((amount[0] - portion[0]) * (amount[1] - portion[1]))


if __name__ == "__main__":
    amount = list(map(int, input().split(' ')))
    portion = list(map(int, input().split(' ')))

    main(amount, portion)

Solution (Python):
H ,W = map(int,input().split())
h ,w = map(int,input().split())

massum = H * W
amariH = H - h
amariW = W - w
result = massum - (h * W + w * (H - h))
print(result)

Solution (Python):
INPUT = [input().split() for l in range(2)]
H=int(INPUT[0][0])
W=int(INPUT[0][1])
h=int(INPUT[1][0])
w=int(INPUT[1][1])
print(H*W-h*W-H*w+h*w)

Solution (Python):
L1 = list(map(int, input().split()))
L2 = list(map(int, input().split()))
print((L1[0]-L2[0])*(L1[1]-L2[1]))

Solution (Python):
H,W = map(int,input().split())
h,w = map(int,input().split())
print(H*W - h*W - w*H + h*w)

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

Solution (Python):
H,W=map(int,input().split())
h,w,=map(int,input().split())

print((H-h)*(W-w))

Solution (Python):
H,W=map(int,input().split())
h,w=map(int,input().split())
print(H*W-(H*w+W*h-h*w))

Solution (Python):
H, W = (int(x) for x in input().split())
h, w = (int(x) for x in input().split())
print(int((H-h)*(W-w)))

Solution (Python):
H, W = map(int, input().split(" "))
h, w = map(int, input().split(" "))

print(H * W - h * W - w * H + h * w)

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

Solution (Python):
H,W = (int(x) for x in input().split())
h,w = (int(x) for x in input().split())

print(H * W - ((h*W + w*H) - h*w))

Solution (Python):
H, W = tuple(map(int, input().split()))
h, w = tuple(map(int, input().split()))
print((H - h) * (W - w))

Solution (Python):
H,W = map(int,input().split())
h,w = map(int,input().split())
print(H*W-h*W-H*w+h*w)

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())
print(H * W - (H * w + h * W - h * w))

Solution (Python):
H,W = map(int,input().split())
h,w = map(int,input().split())

print(H*W - (h*W + w*H - h*w))

Solution (Python):
H,W = (int(i) for i in input().split())
h,w = (int(i) for i in input().split())
print((H-h)*(W-w))

Solution (Python):
def slove():
    import sys
    input = sys.stdin.readline
    a, b = list(map(int, input().rstrip('\n').split()))
    c, d = list(map(int, input().rstrip('\n').split()))
    print((a- c) * (b - d))


if __name__ == '__main__':
    slove()

Solution (Python):
import sys

input = sys.stdin.readline


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


if __name__ == "__main__":
    main()

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())


print(H*W-(h*W+H*w-h*w))

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

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())

print((H-h)*(W-w))

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())

print((H-h)*(W-w))

Solution (Python):
H,W = map(int, input().split())
h,w = map(int, input().split())
white = H*W
black = h*W+w*(H-h)
print(white-black)

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())

ans = H*W - (h*W + w*H - h*w)
print(ans)

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

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

Solution (Python):
h,w,a,b=map(int,open(0).read().split());print(h*w-a*w-b*h+a*b)

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

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

Solution (Python):
H,W = map(int, input().split())
h,w = map(int, input().split())
print(H*W-h*W-w*H+h*w)

Solution (Python):
H, W = map(int, input().split())
h, w = map(int, input().split())
print(H*W-h*W-w*H+w*h)

Solution (Python):


H, W = map(int, raw_input().split())
h, w = map(int, raw_input().split())

ans = (H*W) - ((h*W + w*H) - h*w)

print ans

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

Solution (Python):
a,b=[int(s) for s in input().split()]
aa,bb=[int(s) for s in input().split()]
print((a-aa)*(b-bb))

Solution (Python):
H,W=map(int,input().split())
h,w=map(int,input().split())
lw=H*W-(h*W+H*w-h*w)
print(lw)

Solution (Python):
H,W = map(int,input().split(" "))
h,w = map(int,input().split(" "))

print((H-h)*(W-w))