#include <bits/stdc++.h>
#include <atcoder/modint>
using namespace std;
using namespace atcoder;
//using mint = modint998244353;
using mint = modint1000000007;
using ll = long long;
using ld = long double;
using pll = pair<ll, ll>;
using tlll = tuple<ll, ll, ll>;
constexpr ll INF = 1LL << 60;
template<class T> bool chmin(T& a, T b) {if (a > b) {a = b; return true;} return false;}
template<class T> bool chmax(T& a, T b) {if (a < b) {a = b; return true;} return false;}
ll safemod(ll A, ll M) {return (A % M + M) % M;}
ll divfloor(ll A, ll B) {if (B < 0) {return divfloor(-A, -B);} return (A - safemod(A, B)) / B;}
ll divceil(ll A, ll B) {if (B < 0) {return divceil(-A, -B);} return divfloor(A + B - 1, B);}
#define FINALANS(A) do {cout << (A) << '\n'; exit(0);} while (false) 

int main()
{
  ll N, M, Q;
  cin >> N >> M >> Q;
  vector<vector<ll>> S(N);
  for (ll i = 0; i < Q; i++)
  {
    ll a, b;
    cin >> a >> b;
    a--, b--;
    S.at(a).push_back(b);
  }

  for (ll i = 0; i < N; i++)
  {
    sort(S.at(i).begin(), S.at(i).end(), greater<ll>());
  }

  vector<ll> dp(N + 2, INF);
  dp.at(0) = -INF;
  for (ll i = 0; i < N; i++)
  {
    for (auto s : S.at(i))
    {
      auto it = lower_bound(dp.begin(), dp.end(), s);
      ll ind = it - dp.begin();
      dp.at(ind) = s;
    }
  }
  
  for (ll i = 1; i < N + 2; i++)
  {
    if (dp.at(i) == INF)
      FINALANS(i - 1);
  }
}