def match(W, H, N, SK):
    cnt = 0
    mark_fin = []
    number_fin = []
    #マークのマッチ
    for i in range(N):
        m = SK[i][0]
        if m in mark_fin:
            continue
        m_cnt = 0
        for j in range(N):
            if SK[j][0] == m:
                m_cnt += 1
        cnt += (H - m_cnt)
        mark_fin.append(m)
    #数字のマッチ
    for k in range(N):
        n = SK[k][1]
        if n in number_fin:
            continue
        n_cnt = 0
        mark_fin2 = []
        for l in range(N):
            if SK[l][1] == n:
                n_cnt += 1
                mark_fin2.append(SK[l][0])
        cnt += (W - n_cnt - len(mark_fin) + len(set(mark_fin2)))
        number_fin.append(n)
    return cnt

def main():
    W = int(input())
    H = int(input())
    N = int(input())
    SK = [[0, 0] for x in range(N)]
    for i in range(N):
        SK[i] = list(map(int, input().split()))
    print(match(W, H, N, SK))

if __name__ == '__main__':
    main()