#include<bits/stdc++.h>
#define LL long long
#define F(x,y,z,o) for(int o=x;o<=y;o+=z)
using namespace std;
int a[105][105];
int main()
{
	ios::sync_with_stdio(0);
	cin.tie(0);cout.tie(0);
	int x,y;
	int n,m,k;
	cin>>n>>m>>k;
	F(1,m,1,l)
	{
		cin>>x>>y;
		F(x-1,x+1,1,i)
		{
			F(y-1,y+1,1,j)
			{
				a[i][j]=1;
			}
		}
		a[x-2][y]=1;a[x+2][y]=1;a[x][y-2]=1;a[x][y+2]=1;
	}
	F(1,k,1,l)
	{
		cin>>x>>y;
		F(x-2,x+2,1,i)
		{
			F(y-2,y+2,1,j)
			{
				a[i][j]=1;
			}
		}
	}
	int ans=0;
	F(1,n,1,i)
	{
		F(1,n,1,j)
		{
			if(a[i][j]==0) ans++;
		}
	} 
	cout<<ans;
	return 0;
}