#include <iostream>
#include <queue>
#include <algorithm>
#define ll long long

using namespace std;

struct adat
{
    ll el, veg;
};
vector <adat> x;

bool sorts(const adat& a, const adat& b)
{
    return a.el < b.el;
}

int main()
{
    ll n, m;
    cin >> n >> m;
    //x.resize(m + 1);
    for (ll i = 1; i <= m; ++i)
    {
        ll a, b;
        cin >> a >> b;
        x.push_back({ a, b });
    }
    sort(x.begin(), x.end(), sorts);

    ll hova = 1, db = 0;
    for (ll i = 0; i < m; ++i)
    {
        if (x[i].el > hova)
            ++db;
        if (x[i].veg > hova)
            hova = x[i].veg;
    }
    if (hova != n)
        ++db;
    cout << db;

    return 0;
}