using System;
using System.IO;
using System.Linq;
using System.Collections.Generic;
using System.Text;

public class Program
{

    public void Proc()
    {
        long suitCount = int.Parse(Reader.ReadLine());
        long numberCount = long.Parse(Reader.ReadLine());

        int itemCount = int.Parse(Reader.ReadLine());

        Card[] items = new Card[itemCount];
        for (int i = 0; i < itemCount; i++) {
            items[i] = new Card(Reader.ReadLine().Split(' ').Select(a => long.Parse(a)).ToArray());
        }

        long suit = items.Select(a => a.Suit).Distinct().Count();
        long num = items.Select(a => a.Number).Distinct().Count();
        long ans = suit * numberCount + num * suitCount - (suit * num) - items.Length;
        Console.WriteLine(ans);
    }

    private class Card {
        public long Suit;
        public long Number;
        public Card(long[] inpt) {
            this.Suit = inpt[0];
            this.Number = inpt[1];
        }
    }


    public class Reader
	{
		private static StringReader sr;
		public static bool IsDebug = false;
		public static string ReadLine()
		{
			if (IsDebug)
			{
				if (sr == null)
				{
					sr = new StringReader(InputText.Trim());
				}
				return sr.ReadLine();
			}
			else
			{
				return Console.ReadLine();
			}
		}
		private static string InputText = @"



2
5
1
1 1



";
	}

	public static void Main(string[] args)
	{
#if DEBUG
		Reader.IsDebug = true;
#endif
		Program prg = new Program();
		prg.Proc();
	}
}