#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll MOD = 1000000007;
using P = pair<int,int>;
#define rep(i, n) for(int i = 0; i < n; i++)
#define all(x) (x).begin(),(x).end()

int main(){
    int n,m,q;
    cin >> n >> m >> q;
    int ans = 0;
    vector<int> cx(q,MOD),cy(q,MOD);
    rep(i,q){
        int a,b;
        cin >> a >> b;
        int j = 0;
        while(cx[j]<a && cy[j]<b) j++;
        cx[j] = min(a,cx[j]);
        cy[j] = min(b,cy[j]);
        ans = max(ans, j+1);
    }
    cout << ans << endl;
    return 0;
}