#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;

struct pnt
{
    int p, i;
    bool f;
    bool operator<(const pnt& r) {
        if (p != r.p) return p < r.p;
        return f < r.f;
    }
    pnt(int p, bool f, int i) : p(p), f(f), i(i) {};
    pnt() : p(0), f(false), i(0) {};
};

bool rp[200009];
vector<pnt> v;
vector<int> pv;

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, m; cin >> n >> m;
    for (int i = 0; i < m; i++) {
        int l, r; cin >> l >> r;
        v.push_back(pnt(l, 0, i));
        v.push_back(pnt(r, 1, i));
    }
    sort(v.begin(), v.end());
    for (int i = 0; i < v.size(); i++) {
        if (rp[v[i].i]) continue;
        if (v[i].f) {
            while (!pv.empty()) {
                rp[pv.back()] = true;
                pv.pop_back();
            }
            n--;
        }
        else
            pv.push_back(v[i].i);
    }
    cout << n << '\n';
    return 0;
}