#include <stdio.h>
#include <vector>
#include <algorithm>

int C = 1;
std::pair<int,int> P[1000010];

int check[1000010];
int next[1000010],prev[1000010];
std::vector< std::pair<int,int> > temp;
int main()
{
	int a,b,c;
	scanf("%d%d%d",&a,&b,&c);
	for(int i=1;i<=c;i++) scanf("%d%d",&P[i].first,&P[i].second);
	std::sort(P+1,P+c+1);
	
	for(int i=1;i<=c;i++)
	{
		if(P[i].first!=P[i-1].first) prev[i] = i;
		else prev[i] = prev[i-1];
	}
	for(int i=c;i>=1;i--)
	{
		if(P[i].first!=P[i+1].first) next[i] = i;
		else next[i] = next[i+1];
	}
	
	for(int i=1;i<=c;i++)
	{
		if(i==next[i])
		{
			for(int j=prev[i];j<=i;j++)
			{
				int min = 1, max = C-1;
				int p = 0;
				while(min<=max)
				{
					int h = (min+max)/2;
					if(check[h]<P[j].second)
					{
						p = h;
						min = h+1;
					}
					else max = h-1;
				}
				temp.push_back(std::make_pair(p+1,P[j].second));
			}
			
			while(!temp.empty())
			{
				std::pair<int,int> t = temp.back();
				temp.pop_back();
				if(t.first==C) C++, check[t.first] = t.second;
				else check[t.first] = check[t.first]<t.second?check[t.first]:t.second;
			}
		}
	}
	
	printf("%d",C-1);
}