#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
#define REP(i, n) for (int i = 0; i < (n); ++i)
#define REPR(i, n) for (int i = n - 1; i >= 0; --i)
#define FOR(i, m, n) for (int i = m; i < n; ++i)
#define FORR(i, m, n) for (int i = m; i >= n; --i)
#define ALL(v) (v).begin(),(v).end()
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
const ll INF=1LL<<60;
const int inf=(1<<30)-1;
const int mod=1e9+7;
int dx[8]={1,0,-1,0,-1,-1,1,1};
int dy[8]={0,1,0,-1,-1,1,-1,1};
int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n,m,q;cin >> n >> m >> q;
    vector<vector<int>> e(n+1);
    REP(i,q){
        int a,b;cin >> a >> b;
        e[a-1].push_back(b);
    }
    vector dp(n+1,vector<int>(m+1));
    REP(i,n){
        for(auto x:e[i]){
            chmax(dp[i+1][x],dp[i][x-1]+1);
        }
        REP(j,m){
            chmax(dp[i+1][j+1],max(dp[i][j+1],dp[i+1][j]));
        }
    }
    cout << dp[n][m] << endl;
}