#include <bits/stdc++.h>
using namespace std;
#define f(i,k,n) for(int i=k; i<n; i++)
#define ll long long
const int inf = INT_MAX;

void solve()
{
    int n,m,k;
    cin>>n>>m>>k;
    vector<vector<int>>  a;
    int x,y;
    f(i,0,k)
    {
        cin>>x>>y;
        a.push_back({x,y});
    }
    sort(a.begin(),a.end(),greater<>());
    int c=1;
    int asd=0;
    vector<int> w;
    while(asd<k)
    {
        if(a[asd][0]==n)
        {
            w=a[asd];
        }
        asd++;
    }
    int o=w[1];
    int t=1;
    int count=0;
    while(t<k)
    {
        if(w[0]!=a[t][0] && a[t][1]>w[1])
        {
            w=a[t];
            c++;
        }
        t++;
    }
    cout<<c;
}

int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    int t=1;
    //cin>>t;
    while(t--)  solve();
    return 0;
}