wlist = []
hlist = []

for i in range(n):
    a, b = [ int(v) for v in input().split() ]
    if a not in wlist:
        wlist.append(a)
    if b not in hlist:
        hlist.append(b)


lw = len(wlist)
lh = len(hlist)

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