#include <iostream>
#include <vector>
#include <cmath>
#include <map>
#include <set>
#include <iomanip>
#include <queue>
#include <algorithm>
#include <numeric>
#include <deque>
#include <complex>
#include <cassert>

using namespace std;
using ll = long long;

int main(){

    int N, M, Q, a, b;
    cin >> N >> M >> Q;
    set<pair<int, int>> st;
    for (int i=0; i<Q; i++){
        cin >> a >> b;
        st.insert({a, b});
    }

    vector<vector<int>> dp(N+1, vector<int>(M+1));

    for (int i=1; i<=N; i++){
        for (int j=1; j<=M; j++){
            dp[i][j] = max(dp[i-1][j], dp[i][j-1]);
            if (st.count({i, j})) dp[i][j] = max(dp[i][j], dp[i-1][j-1]+1);
        }
    }

    cout << dp[N][M] << endl;

    return 0;
}