#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int maxX, maxY, max;
int * pole;

inline int map(int x, int  y) {
//	printf("mapuju %d %d na %d\n", x, y,x + y * maxX );
	return (x +( y * maxX ));
}



/**
 radek 1
 sloupec 2
 zhora dolu 4
 zdola nahoru 8
*/

void readQueen() {
	int posX, posY, i;
	scanf("%d %d", &posX, &posY);
	posX -=1; posY -=1;

	int stav = pole[map(posX,posY)];
//	printf("stav %d\n", stav);
	
	if (! (stav & 1)) {
	for ( i = 0; i < maxX; ++i ){
		pole[map(i,posY)] += 1;
	}}
	if (!(stav & 2)) {
	for ( i = 0; i < maxY; ++i ){
		pole[map(posX,i)] += 2;
	}}
	if (!(stav & 4)) {
		for ( i = 0; (i+posX)<maxX && (i+posY)<maxY; ++i ){
			pole[map(posX + i,posY + i)] += 4;
		}
		for ( i = 0; (posX-i)>=0 && (posY-i)>=0; ++i ){
			pole[map(posX - i,posY - i)] += 4;
		}		
	}
	if (!(stav & 8)) {
		for ( i = 0; (posX-i)>=0 && (i+posY)<maxY; ++i ){
			pole[map(posX - i,posY + i)] += 8;
		}
		for ( i = 0; (i+posX)<maxX && (posY-i)>=0; ++i ){
			pole[map(posX + i,posY - i)] += 8;
		}		
	}
}


int main() {
	int pocet, i;

	scanf("%d %d %d", &maxX, &maxY, &pocet);

	while ( maxX || maxY || pocet )
	{
		max = 	maxX * maxY;
	    	pole = (int*)malloc(sizeof(int)*(max));
		for ( i = 0; i<max; ++i) pole[i]=0;

		for (i = 0; i < pocet; ++i)
		{
			readQueen();
		}

		int suma = 0;
		for (i = 0; i < max; ++i)
		{
			if (pole[i] == 0) ++suma;
		}
		printf("%d\n", suma);
		scanf("%d %d %d", &maxX, &maxY, &pocet);
		free (pole);
	}

	return 0;
}


/*
int mapPos(int x, int y, int delka, int sirka)
{
	return (y*delka+x);
}


int main()
{
	int delka, sirka, pocet, i, j, posX, posY;
	scanf("%d %d %d", &delka, &sirka, &pocet);
	while ( delka || sirka || pocet )
	{		
		int * pole = (int*)malloc(sizeof(int)*(delka*sirka));
		
		for (i = 0; i < (delka*sirka); ++i) pole[i] = 1;
		for (i = 0; i < pocet; ++i)
		{
			scanf("%d %d", &posX, &posY);
			posX-=1; posY-=1;
			for (j = posX; j < (delka*sirka); j+=delka) pole[j] = 0;
			for (j = mapPos(0, posY, delka, sirka); j < mapPos(delka, posY, delka, sirka); ++j) pole[j] = 0;
			for (j = mapPos(posX, posY, delka, sirka); j < (delka*sirka); j+=(delka+1)) {if ((j%delka)>posX) pole[j] = 0; else break;}
			for (j = mapPos(posX, posY, delka, sirka); j < (delka*sirka); j+=(delka-1)) {if ((j/delka)<posX) pole[j] = 0; else break;}
			for (j = mapPos(posX, posY, delka, sirka); j >= 0; j -= (delka-1) ) {if ((j/delka)>posX) pole[j] = 0; else break;}
			for (j = mapPos(posX, posY, delka, sirka); j >= 0; j -= (delka+1) ) {if ((j/delka)<posX) pole[j] = 0; else break;}
		}
		int suma = 0;
		for (i = 0; i < (delka*sirka); ++i)
		{
			if (pole[i] == 1) ++suma;
		}
		printf("%d\n", suma);
		free (pole);
		scanf("%d %d %d", &delka, &sirka, &pocet);
	}
	return 0;
}*/