#include <bits/stdc++.h>
using namespace std;

int inf = 1001001001;

template <typename T>
struct SegmentTree {
    int n;
    vector<T> dat;
    SegmentTree() {}
    SegmentTree(int N) {
        n = 1;
        while(n < N) {
            n *= 2;
        }
        dat.resize(2*n-1,-inf);
    }
    void update(int x, T val) {
        x += (n-1);
        dat[x] = val;
        while(x > 0) {
            x = (x-1)/2;
            dat[x] = max(dat[2*x+1],dat[2*x+2]);
        }
    }
    T query(int a, int b, int k, int l, int r) {
        if(r <= a || b <= l) return -inf;
        if(a <= l && r <= b) return dat[k];
        T vl = query(a, b, 2*k+1, l, (l+r)/2);
        T vr = query(a, b, 2*k+2, (l+r)/2, r);
        return max(vl, vr);
    }
    T query(int a,int b) {//[a,b)
        return query(a,b,0,0,n);
    }
};

int main() {
    int N,M,Q;
    cin >> N >> M >> Q;
    map<int,vector<int>>tmp;
    for(int i = 0; i < Q; i++) {
        int a,b;
        cin >> a >> b;
        tmp[a].push_back(b);
    }
    SegmentTree<int>Seg(M+1);
    Seg.update(0,0);
    for(auto x:tmp) {
        sort(x.second.rbegin(),x.second.rend());
        for(int i = 0; i < x.second.size(); i++) {
            Seg.update(x.second[i],Seg.query(0,x.second[i])+1);
        }
    }
    cout << Seg.query(0,M+1) << endl;
}