using namespace std;
int a[105][105];
int main(){
	int ans=0,n,m,k,i,j,x,y;
	cin>>n>>m>>k;
	for(i=1;i<=m;i++){
		cin>>x>>y;
		if(a[x][y]==0) a[x][y]=1;
		if(a[x-2][y]==0) a[x-2][y]=1;
		if(a[x-1][y]==0) a[x-1][y]=1;
		if(a[x+1][y]==0) a[x+1][y]=1;
		if(a[x+2][y]==0) a[x+2][y]=1;
		if(a[x][y+1]==0) a[x][y+1]=1;
		if(a[x][y+2]==0) a[x][y+2]=1;
		if(a[x][y-1]==0) a[x][y-1]=1;
		if(a[x][y-2]==0) a[x][y-2]=1;
		if(a[x-1][y-1]==0) a[x-1][y-1]=1;
		if(a[x+1][y-1]==0) a[x+1][y-1]=1;
		if(a[x+1][y+1]==0) a[x+1][y+1]=1;
		if(a[x-1][y+1]==0) a[x-1][y+1]=1;
	}
	for(i=m;i<=k;i++){
		cin>>x>>y;
		if(a[x][y]==0) a[x][y]=1;
		if(a[x-2][y]==0) a[x-2][y]=1;
		if(a[x-1][y]==0) a[x-1][y]=1;
		if(a[x+1][y]==0) a[x+1][y]=1;
		if(a[x+2][y]==0) a[x+2][y]=1;
		if(a[x][y+1]==0) a[x][y+1]=1;
		if(a[x][y+2]==0) a[x][y+2]=1;
		if(a[x][y-1]==0) a[x][y-1]=1;
		if(a[x][y-2]==0) a[x][y-2]=1;
		if(a[x-1][y-1]==0) a[x-1][y-1]=1;
		if(a[x+1][y-1]==0) a[x+1][y-1]=1;
		if(a[x+1][y+1]==0) a[x+1][y+1]=1;
		if(a[x-1][y+1]==0) a[x-1][y+1]=1;
		if(a[x-2][y-2]==0) a[x-2][y-2]=1;
		if(a[x+2][y-2]==0) a[x+2][y-2]=1;
		if(a[x+2][y+2]==0) a[x+2][y+2]=1;
		if(a[x-2][y+2]==0) a[x-2][y+2]=1;
		if(a[x-2][y-1]==0) a[x-2][y-1]=1;
		if(a[x-1][y-2]==0) a[x-1][y-2]=1;
		if(a[x-2][y+1]==0) a[x-2][y+1]=1;
		if(a[x-1][y+1]==0) a[x-1][y+1]=1;
		if(a[x+1][y+2]==0) a[x+1][y+2]=1;
		if(a[x+2][y+1]==0) a[x+2][y+1]=1;
		if(a[x+1][y-2]==0) a[x+1][y-2]=1;
		if(a[x+2][y-1]==0) a[x+2][y-1]=1;
	}
	for(i=1;i<=n;i++){
		for(j=1;j<=n;j++){
			if(a[i][j]==0) ans++;
		}
	}
	cout<<ans;
	return 0;
}