ll c[1001][1001],d[][];
{
	ll@n,@m,@q;
	rep(q){
		ll@a,@b;
		c[a][b]=1;
	}
	rep(x,1,n+1){
		rep(y,1,m+1){
			d[x][y]=max(d[x-1][y],d[x][y-1])+c[x][y];
		}
	}
	wt(d[n][m]);
}