w = gets.to_i
h = gets.to_i
n = gets.to_i

s_counter = Hash.new(0)
k_counter = Hash.new(0)

n.times do
  s, k = gets.split.map(&:to_i)
  s_counter[s] += 1
  k_counter[k] += 1
end

sum = 0
cross = 0
s_counter.values.each do |c|
  sum += h - c
  cross += k_counter.size - c
end
k_counter.values.each do |c|
  sum += w - c
  cross += s_counter.size - c
end

puts sum - cross / 2