#include <iostream>
#include <algorithm>
#include <iomanip>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <tuple>
#include <cmath>
#include <numeric>
#include <functional>
#include <cassert>

#define debug_value(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << #x << "=" << x << endl;
#define debug(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << x << endl;

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

using namespace std;
typedef long long ll;
using P = pair<int, int>;
const int INF = 1e9;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << setprecision(10) << fixed;
    int n, m, q; cin >> n >> m >> q;
    vector<int> a(q), b(q);
    vector<P> vp;
    for(int i = 0; i < q; i++) {
        cin >> a[i] >> b[i]; a[i]--; b[i]--;
        vp.push_back(P(a[i], -b[i]));
    }
    sort(vp.begin(), vp.end());
    vector<int> dp(m+1, INF);
    dp[0] = -1;
    for(auto p: vp){
        int x = -p.second;
        auto pt = lower_bound(dp.begin(), dp.end(), x);
        int i = pt-dp.begin();
        dp[i] = x;
    }
    for(int i = m; i >= 0; i--){
        if(dp[i] != INF){
            cout << i << endl;
            return 0;
        }
    }
}