#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint1000000007;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000000

int op(int a,int b){
	return max(a,b);
}

int e(){
	return 0;
}



int main(){
	
	int n,m,q;
	cin>>n>>m>>q;
	
	vector<vector<int>> E(n);
	rep(i,q){
		int x,y;
		scanf("%d %d",&x,&y);
		x--;y--;
		E[x].push_back(y);
	}
	
	segtree<int,op,e> seg(m);
	
	rep(i,n){
		sort(E[i].rbegin(),E[i].rend());
		rep(j,E[i].size()){
			int b = E[i][j];
			seg.set(b,max(seg.get(b),seg.prod(0,b)+1));
		}
	}
	
	cout<<seg.all_prod()<<endl;
	
	return 0;
}