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/*
ID:du331691
PROG:rectbarn
LANG:C++
*/
#include<iostream>
#include<cstring>
#include<cstdio>
#include<cstdlib>
#include<algorithm>
using namespace std;
template<typename T>
void read(T& w)
{
	char r;
	for(r=getchar();r<48||r>57;r=getchar());
	for(w=0;r>=48&&r<=57;r=getchar())w=w*10+r-48;
}
template<typename T>
T Min(const T& a,const T& b){return a<b?a:b;}
template<typename T>
T Max(const T& a,const T& b){return a>b?a:b;}
const int maxn=3003;
const int maxp=30003;
int n,m,p;
bool tree[maxn][maxn];
int height[2][maxn];
int treel[2][maxn],treer[2][maxn];
int Left[2][maxn],Right[2][maxn];
void input()
{
	read(n),read(m),read(p);
	int x,y;
	for(int i=1;i<=p;++i)
	{
		read(x),read(y);
		tree[x][y]=true;
	}

}
int ans=0;
void dp()
{
	for(int j=1;j<=m;++j)
		tree[0][j]=tree[n+1][j]=true;
	for(int i=2;i<=n-1;++i)
	{
		tree[i][0]=tree[i][m+1]=true;
	}
	
	for(int i=1;i<=n;++i)
	{
		int now=i&1,lst=i&1^1;
				
		for(int j=1,last=0;j<=m;++j)
		{
			if(tree[i][j])
				last=j;
			treel[now][j]=last;
		}
		for(int j=m,last=m+1;j>=1;--j)
		{
			if(tree[i][j])
				last=j;
			treer[now][j]=last;
		}
		for(int j=1;j<=m;++j)
		{
			if(tree[i-1][j])
			{
				height[now][j]=1;
				Left[now][j]=treel[now][j];
				Right[now][j]=treer[now][j];
			}
			else
			{
				height[now][j]=height[lst][j]+1;
				Left[now][j]=Max(treel[now][j],Left[lst][j]);
				Right[now][j]=Min(treer[now][j],Right[lst][j]);
			}
			if(!tree[i][j])
			{
				int tans=(Right[now][j]-Left[now][j]-1)*height[now][j];
				if(tans>ans)
					ans=tans;
			}
		}

	}
}
int main()
{
	freopen("rectbarn.in","r",stdin);
	freopen("rectbarn.out","w",stdout);
	input();
	dp();
	printf("%d\n",ans);
	return 0;
}