#include <bits/stdc++.h>
#define rep(i, l, r) for (int i = (l); i < (r); i++)
using namespace std;

typedef long long ll;

int main() {
    int N, M, Q, a, b;
    cin >> N >> M >> Q;
    vector<vector<bool>> ok(N, vector<bool>(M, false));
    rep(i, 0, Q) {
        cin >> a >> b;
        ok[a - 1][b - 1] = true;
    }
    vector<vector<int>> dp(N + 1, vector<int> (M + 1, 0));
    rep(i, 0, N) {
        rep(j, 0, M) {
            dp[i + 1][j + 1] = max(dp[i][j + 1], dp[i + 1][j]);
            if (ok[i][j]) dp[i + 1][j + 1] = max(dp[i + 1][j + 1], dp[i][j] + 1);
        }
    }
    cout << dp[N][M] << endl;
    /*
    rep(i, 0, N + 1) {
        rep(j, 0, M + 1) {
            cout << dp[i][j] << " ";
        }
        cout << endl;
    }
    */
}