import java.io.*;
import java.util.*;

class Main {
	
	public static void out (Object o) {
		System.out.println(o);
	}
	
	public static void main (String[] args) throws IOException {
		BufferedReader br = 
			new BufferedReader(new InputStreamReader(System.in));
		
		int markCnt = Integer.parseInt(br.readLine());
		int maxNum = Integer.parseInt(br.readLine());
		int n = Integer.parseInt(br.readLine());
		int[] marks = new int[markCnt + 1];
		ArrayList<Integer> numList = new ArrayList<Integer>();
		
		for (int i = 0; i < n; i++) {
			String[] line = br.readLine().split(" ");
			int mark = Integer.parseInt(line[0]);
			int num = Integer.parseInt(line[1]);
			
			marks[mark]++;
			if (!numList.contains(num)) {
				numList.add(num);
			}
		}
		
		long ans = 0;
		for (int i = 1; i <= markCnt; i++) {
			if (marks[i] == 0) {
				ans += numList.size();
			} else {
				ans += maxNum - marks[i];
			}
		}
		
		out(ans);
		
	}
}