class Yukicoder
  def initialize
    w = gets.to_i
    h = gets.to_i
    n = gets.to_i

    marks = Array.new(w, false)
    nums = Hash.new(false)
    sum = 0

    n.times do
      s, k = gets.chomp.split.map{|i| i.to_i-1}

      if !marks[s]
        marks[s] = true
      end

      if !nums[k]
        nums[k] = true
        sum += 1
      end
    end

    answer = 0

    marks.each do |mark|
      num = 0

      if mark
        num += h
      else
        num += sum
      end

      answer += num
    end

    puts answer - n
  end
end

Yukicoder.new