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

buff = []
for w1 in range(W):
    buff.append([0 for h1 in range(H)])

for w2 in range(w):
    for x in range(H):
        buff[w2][x] = 1
    for h2 in range(h):
        for x in range(W):
            buff[x][h2] = 1
c = 0
for b in buff:
    for a in b:
        if a == 0:
            c+=1
print(c)

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 - 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())

s = (H-h) * (W-w)

print(s)

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

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

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

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-h)*(W-w))

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

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

Solution (Python):
def abc():
    ROW, COL = map(int, input().rstrip().split())
    row, col = map(int, input().rstrip().split())

    squares = ROW * COL
    squares -= (row * COL)
    squares -= (col * (ROW - row))
    print(squares)


abc()

Solution (Python):
inp = input().split()
all_h = int(inp[0])
all_w = int(inp[1])

inp_select = input().split()
h = int(inp_select[0])
w = int(inp_select[1])

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

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

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

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):
'''
allinputs = iter(input().splitlines())
input = lambda : next(allinputs)

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

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

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())

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

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

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):
lhlw = input().split()
hw = input().split()

lh_h = int(lhlw[0]) - int(hw[0])
lw_w = int(lhlw[1]) - int(hw[1])
result = lh_h * lw_w
print(result)

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

white = H * W
black = h * W + H * w -(h * w)

print(white - black)

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

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

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

Solution (Python):
HW = input().split()
hw = input().split()
HW[0] = int(HW[0])
HW[1] = int(HW[1])
hw[0] = int(hw[0])
hw[1] = int(hw[1])
count = 0

HW_list = [[0] * HW[1] for i in range(HW[0])]

for i in range(0, hw[0]):
    for j in range(0, len(HW_list[0])):
        HW_list[i][j] = 1

for i in range(0, hw[1]):
    for j in range(0, len(HW_list)):
        HW_list[j][i] = 1

for i in range(0, HW[0]):
    for j in range(0, HW[1]):
        if HW_list[i][j] == 0:
            count += 1

print(count)

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 - w * h))

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

white_square_number = (H-h) * (W-w)
print(int(white_square_number))

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())

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

print(white)

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

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

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 * 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):

a,b = map(int,input().split())
A,B = map(int,input().split())
print((a-A)*(b-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] = 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((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 = map(int,input().split())
h,w = map(int,input().split())


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

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 = 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-h)*(W-w))

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

grid = H * W

grid = grid - h * W
grid = grid - w * (H - h)

print(grid)

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

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

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

Solution (Python):
l=[]
for i in range(2):
  l.append(input().split())
a=int(l[0][0])-int(l[1][0])
b=int(l[0][1])-int(l[1][1])
print(a*b)

Solution (Python):
HW = input().split()
hw = input().split()

H = int(HW[0])
W = int(HW[1])
h = int(hw[0])
w = int(hw[1])

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

Solution (Python):
data = list(map(int,input().split()))
H = data[0]
W = data[1]
data = list(map(int,input().split()))
h = data[0]
w = data[1]
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())
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 + 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())

line = H - h
column = W - w
print(line * column)

Solution (Python):
from collections import defaultdict, Counter
from itertools import product, groupby, count, permutations, combinations
from math import pi, sqrt
from collections import deque
from bisect import bisect, bisect_left, bisect_right
from string import ascii_lowercase
from functools import lru_cache
import sys
sys.setrecursionlimit(10000)
INF = float("inf")
YES, Yes, yes, NO, No, no = "YES", "Yes", "yes", "NO", "No", "no"
dy4, dx4 = [0, 1, 0, -1], [1, 0, -1, 0]
dy8, dx8 = [0, -1, 0, 1, 1, -1, -1, 1], [1, 0, -1, 0, 1, 1, -1, -1]


def inside(y, x, H, W):
    return 0 <= y < H and 0 <= x < W


def ceil(a, b):
    return (a + b - 1) // b



def gcd(a, b):
    if b == 0:
        return a
    return gcd(b, a % b)



def lcm(a, b):
    g = gcd(a, b)
    return a / g * b


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):
a,b=map(int,input().split())
c,d=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())
    Ans = (H-h)*(W-w)
    print(Ans)


if __name__ == "__main__":
    main()

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

Solution (Python):
hh, ww = map(int, input().split())
h, w = map(int, input().split())

print(int((hh-h)*(ww-w)))

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

Solution (Python):

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


if __name__ == "__main__":
    main()

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

kuro = ((H * w) + (W * h)) - (w * h)
siro = (H * W) - kuro

print(siro)

Solution (Python):
lst1 = input().split()
lst2 = input().split()
H = int(lst1[0])
W = int(lst1[1])
h = int(lst2[0])
w = int(lst2[1])

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((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 = 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())

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

    print(H * W - (h * W) - (H * w) + (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 = [int(e) for e in input().split(" ")]
h, w = [int(e) for e in input().split(" ")]

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

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

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

Solution (Python):
if __name__ == "__main__":
    list_1=input().split()
    H=int(list_1[0])
    W=int(list_1[1])

    list_2=input().split()
    h=int(list_2[0])
    w=int(list_2[1])
    
    Ans = (H-h)*(W-w)
    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())

if h == H or w == H:
    print(0)
else:
    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):
a, b = input().split()
a, b = int(a), int(b)

c,d = input().split()
c,d = int(c), int(d)

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):
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,M = map(int,input().split())
h,m = map(int,input().split())
print((H-h)*(M-m))

Solution (Python):


import sys


s2nn = lambda s: map(int, s.split(' '))
ss2nn = lambda ss: map(int, ss)
ss2nnn = lambda ss: [s2nn(s) for s in ss]
i2s = lambda: sys.stdin.readline().rstrip()
i2n = lambda: int(i2s())
i2nn = lambda: s2nn(i2s())
ii2ss = lambda n: [sys.stdin.readline().rstrip() for _ in range(n)]
ii2nn = lambda n: ss2nn(ii2ss(n))
ii2nnn = lambda n: ss2nnn(ii2ss(n))

def main():
    H, W = i2nn()
    h, w = i2nn()
    n = (H - h) * (W - w)
    print(n)

main()

Solution (Python):


import sys

s2nn = lambda s: map(int, s.split(' '))
ss2nn = lambda ss: map(int, ss)
ss2nnn = lambda ss: [s2nn(s) for s in ss]
i2s = lambda: sys.stdin.readline().rstrip()
i2n = lambda: int(i2s())
i2nn = lambda: s2nn(i2s())
ii2ss = lambda n: [sys.stdin.readline().rstrip() for _ in range(n)]
ii2nn = lambda n: ss2nn(ii2ss(n))
ii2nnn = lambda n: ss2nnn(ii2ss(n))

def main():
    H, W = i2nn()
    h, w = i2nn()
    n = (H - h) * (W - w)
    print(n)

main()

Solution (Python):


import sys
import numpy as np

s2nn = lambda s: map(int, s.split(' '))
ss2nn = lambda ss: map(int, ss)
ss2nnn = lambda ss: [s2nn(s) for s in ss]
i2s = lambda: sys.stdin.readline().rstrip()
i2n = lambda: int(i2s())
i2nn = lambda: s2nn(i2s())
ii2ss = lambda n: [sys.stdin.readline().rstrip() for _ in range(n)]
ii2nn = lambda n: ss2nn(ii2ss(n))
ii2nnn = lambda n: ss2nnn(ii2ss(n))

def main():
    H, W = i2nn()
    h, w = i2nn()
    n = (H - h) * (W - w)
    print(n)

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):
HW = list(map(lambda x: int(x), input().split()))
H = HW[0]
W = HW[1]

hw = list(map(lambda x: int(x), input().split()))
h = hw[0]
w = hw[1]

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

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

Solution (Python):

import sys


def solve(H: int, W: int, h: int, w: int):
    res = (H-h)*(W-w)
    print(res)
    return



def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    H = int(next(tokens))  
    W = int(next(tokens))  
    h = int(next(tokens))  
    w = int(next(tokens))  
    solve(H, W, h, w)

if __name__ == '__main__':
    main()

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("{}".format((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(HW) for HW in input().split()]
h, w = [int(hw) for hw in input().split()]
n = H*W - h*W -H*w + h*w
print(n)

Solution (Python):

l = list(map(int, input().split(' ')))
s = list(map(int, input().split(' ')))

print(int((l[1]-s[1])*(l[0]-s[0])))

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 ("{}".format((H-h)*(W-w)))

Solution (Python):


h, w = map(int, input().split())
delH, delW = map(int, input().split())

print((h-delH)*(w-delW))

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-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 collections import defaultdict
import sys,heapq,bisect,math,itertools,string,queue,datetime
sys.setrecursionlimit(10**8)
INF = float('inf')
mod = 10**9+7
eps = 10**-7
def inpl(): return list(map(int, input().split()))
def inpl_str(): return list(input().split())

H,W = inpl()
h,w = inpl()

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

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

if __name__ == '__main__':
    main()

Solution (Python):
import sys


def input():
    return sys.stdin.readline()[:-1]








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

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

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

Solution (Python):
H, W = [int(i) for i in input().split()]
h, w = [int(i) for i in 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):
H1,W1=map(int,input().split())
H2,W2=map(int,input().split())
print((W2-W1)*(H2-H1))

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
sH, sW = stdin.readline().split()
sh, sw = stdin.readline().split()
H, W = int(sH), int(sW)
h, w = int(sh), int(sw)
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*W - h*W - H*w + h*w)

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

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

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

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, 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())

H -= h
W -= w

print(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())

S = H * W
s = h * W + w * H - h * w

print(S - s)

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())

field = H * W
white = field - h * W - (w * (H - h))

print(white)

Solution (Python):
hh, ww = map(int, input().split())
h, w = map(int, input().split())
count = (hh * ww) - (h * ww) - (w * (hh - h))
print(str(count))

Solution (Python):
h, w = map(int, input().split())
hh, ww = map(int, input().split())

print(h * w - (w * hh + h * ww - (hh * ww)))

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

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


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

total = H * W
row_black = W * h
col_black = H * w
duplicate = h * w

print(total - row_black - col_black + duplicate)

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):
W, H = map(int, input().split())
sw, sh = map(int, input().split())

print(W*H -sw*H -sh*W + sw*sh)

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 = [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):
a,b =(int(x) for x in input().split())
c,d =(int(i) for i in input().split())
print(a*b-a*d-b*c+c*d)

Solution (Python):
lh,lw = map(int,input().split(" "))
h,w = map(int,input().split(" "))

print((lh-h)*(lw-w))

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

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

Solution (Python):
import sys
rr = lambda: sys.stdin.readline().strip()
ri = lambda: int(rr())
rs = lambda: [int(_) for _ in rr().split()]

H, W = rs()
h, w = rs()

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

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

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

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

Solution (Python):
H,W=(map(int,input().split()))
h,w=(map(int,input().split()))
a=0
b=0
a=H*W
b=H*w+W*h-w*h
print(a-b)

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

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

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())

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

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-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("{}".format((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 - w * H - h * W + h * w)

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

Solution (Python):
import sys
input = sys.stdin.readline

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

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

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

Solution (Python):
if __name__ == '__main__':
    input_list = list(map(int, input().split()))
    H = input_list[0]
    W = input_list[1]
    input_list = list(map(int, input().split()))
    h = input_list[0]
    w = input_list[1]

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

    print(answer)

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

sum = H * W
cnt = (W * h) + (w * (H - h))
print(sum - cnt)

Solution (Python):
H,W,h,w = map(int, open(0).read().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())

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

print(white)

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

Solution (Python):


from bisect import bisect_left as binl

def intin():
    input_tuple = input().split()
    if len(input_tuple) <= 1:
        return int(input_tuple[0])
    return map(int, input_tuple)


def intina():
    return [int(i) for i in input().split()]


def intinl(count):
    return [intin() for _ in range(count)]


def lcm(x, y):
    while y != 0:
        z = x % y
        x = y
        y = z
    return x





def main():
    H, W = intin()
    h, w = intin()

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


if __name__ == '__main__':
    main()

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=list(map(int,input().split()))
a=list(map(int,input().split()))
print(A[0]*A[1]-(a[0]*A[1]+a[1]*A[0]-a[0]*a[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-W*h+w*h)

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

Solution (Python):
A,B=map(int,input().split())
a,b=map(int,input().split())

x=A-a
y=B-b

print(int(x*y))

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 + w * H - h * w))

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

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