/* -*- coding: utf-8 -*-
 *
 * 1703.cc:  No.1703 Much Matching - yukicoder
 */

#include<cstdio>
#include<algorithm>

using namespace std;

/* constant */

const int MAX_N = 1000;
const int MAX_M = 1000;

/* typedef */

/* global variables */

bool ts[MAX_N][MAX_M];
int dp[MAX_N + 1][MAX_M + 1];

/* subroutines */

inline void setmax(int &a, int b) { if (a < b) a = b; }

/* main */

int main() {
  int n, m, q;
  scanf("%d%d%d", &n, &m, &q);

  for (int i = 0; i < q; i++) {
    int ai, bi;
    scanf("%d%d", &ai, &bi);
    ai--, bi--;
    ts[ai][bi] = true;
  }

  for (int i = 0; i <= n; i++)
    for (int j = 0; j <= m; j++) {
      if (i < n && j < m && ts[i][j])
	setmax(dp[i + 1][j + 1], dp[i][j] + 1);
      if (i < n) 
	setmax(dp[i + 1][j], dp[i][j]);
      if (j < m) 
	setmax(dp[i][j + 1], dp[i][j]);
    }

  printf("%d\n", dp[n][m]);
  return 0;
}