/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

import java.util.Scanner;

/**
 *
 * @author cteam48
 */
public class ith {

    /**
     * @param args the command line arguments
     */
    


    
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String input = new String();
        int X;
        int Y;
        int Xk = 0;
        int Yk = 0;
        int N;
        int vystup;
        boolean Xdobre; // neohrozuje kralovna na X
        boolean Ydobre;// neohrozuje kralovna na Y
        boolean Ddobre;// neohrozuje kralovna na diagonale
        boolean konec = false;
        // TODO code application logic here
        while(konec==false) {
            X  = sc.nextInt();
            Y = sc.nextInt();
            N = sc.nextInt();
            if(X==0 && Y==0 && N==0) {
                konec = true;
            } else {
                
                boolean sachovnice[][] = new boolean[X][Y];
                for (int i = 0; i < X; i++) {
                    for (int j = 0; j < Y; j++) {
                        sachovnice[i][j] = false;
                    }
                }
                
                for(int i=0; i<N; i++) {
                    Xk = sc.nextInt();
                    Yk = sc.nextInt();
                    sachovnice[Xk-1][Yk-1] = true;
                }
        
            vystup = 0;
                
         
            for (int i = 0; i < X; i++) {
                    for (int j = 0; j < Y; j++) {
                        Xdobre =true;
                        Ydobre = true;
                        Ddobre = true;
                    
                        for (int k = 0; k < X; k++) {
                            if(sachovnice[k][j]==true) Xdobre = false; 
                        }

                        for (int k = 0; k < Y; k++) {
                            if(sachovnice[i][k]==true) Ydobre = false; 
                        }
                        
                       
                        for (int k = 0; k < sachovnice.length; k++) {
                        //DOLEVA NAHORU
                            if(i-k>=0 && j-k>=0) {
                                if(sachovnice[i-k][j-k]==true) Ddobre=false;
                            }
                        //DOPRAVA NAHORU
                            if(i+k<X && j-k>=0) {
                                if(sachovnice[i+k][j-k]==true) Ddobre=false;
                            }
                            
                        //DOLEVA DOLU
                            if(i-k>=0 && j+k<Y) {
                                if(sachovnice[i-k][j+k]==true) Ddobre=false;
                            }
                        //DOPRAVA DOLU
                            if(i+k<X && j+k<Y) {
                                if(sachovnice[i+k][j+k]==true) Ddobre=false;
                            }   
                        }

                        if (Xdobre && Ydobre && Ddobre) vystup++;
                        
                    }
            }

        
            System.out.println(vystup);
        
         }
        }
    }

}