W = int(input())
H = int(input())
N = int(input())
hand = [tuple(map(int, input().split())) for i in range(N)]
hset = set(hand)
cntmark = [H] * (W + 1)
cntmark[0] = 0
cntnum = [W] * (H + 1)
cntnum[0] = 0
for m, n in hand:
    cntmark[m] -= 1
    cntnum[n] -= 1
ans = 0
donem = set()
donen = set()
for m, n in hand:
    if m not in donem:
        ans += cntmark[m]
        donem.add(m)
    if n not in donen:
        ans += cntnum[n]
        donen.add(n)
for i in range(N):
    mi, ni = hand[i]
    for j in range(i + 1, N):
        mj, nj = hand[j]
        if (mi, nj) not in hset:
            ans -= 1
            hset.add((mi, nj))
        if (mj, ni) not in hset:
            ans -= 1
            hset.add((mj, ni))
print(ans)