// Source: https://usaco.guide/general/io

#include <bits/stdc++.h>
using namespace std;

int main() {
	ios_base::sync_with_stdio(0); cin.tie(0);
	int n, m, k; cin>>n>>m>>k;
	vector<vector<int>> v(n);
	set<int> vanbenne;
	for(int i = 0; i < k; i++){
		int a, b; cin>>a>>b; a--; b--;
		v[a].push_back(b);
		vanbenne.insert(a);
	}
	for(auto&i:v)sort(i.begin(), i.end());
	int ans = 0;
	while(k){
		ans++;
		int x = 0;
		auto it = vanbenne.begin();
		while(it != vanbenne.end()){
			int i = *it;
			bool b = false;
			int ujx = x;
			while(!v[i].empty() && v[i].back() >= x){
				if(!b){
					b = true;
					ujx = v[i].back();
				}
				v[i].pop_back();
				k--;
			}
			if(v[i].empty()){
				it = vanbenne.erase(it);
			} else {
				it = next(it);
			}
			x = ujx;
		}
	}
	cout<<ans<<endl;
}