/*
	@・ω・@ <だれだろうね
*/

/*****/

#include <iostream>
#include <array>
#include <vector>
#include <algorithm>
#include <string>
#include <cmath>
#include <queue>
#include <stack>
#include <map>
#include <iomanip>	//cout << fixed << setprecision(桁数);
#include <stdexcept>

//#define int long long

using namespace std;
using ll = long long;
using ld = long double;
using vecll = vector<long long>;
using pll = pair<long long, long long>;
template<class T> using pr = pair<T, T>;
template<class T> using vec = vector<T>;

#define debug(x) (std::cerr << (x) << "\n")
#define debug_tab(n, x) (std::cerr << strMulti("\t",n) << (x) << "\n")
#define debug_cout(x) (std::cerr << #x << " : " <<  (x) << "\n")
#define debug_tabcout(n, x) (std::cerr << strMulti("\t",n) << #x << " : " <<  (x) << "\n")
#define debug_headcout(h, x) (std::cerr << (h) << " : " <<  (x) << "\n")
#define debug_tabheadcout(n, h, x) (std::cerr << strMulti("\t",n) << (h) << " : " <<  (x) << "\n")

#define str(n)	(n.toString())

#define rep(i, n) for(ll i=0, i##_len=(n); i<i##_len; ++i)
#define rep1(i, n) for(ll i=1, i##_len=(n); i<=i##_len; ++i)
#define rrep(i, n) for(ll i=(n)-1; i >= 0; --i)
#define rrep1(i, n) for(ll i=(n); i > 0; --i)
#define all(x) (x).begin(), (x).end()
#define pair(a, b) make_pair(a, b)
constexpr int INF = 2000000100;
constexpr ll MOD = 1000000007;	// 10e9+7
template<class T> bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
template<class T> bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
template<class T> T divup(T a, T b) { if (a % b == 0) { return a / b; } return a / b + 1; }
std::string strMulti(std::string t, int n) { std::string out = ""; for (int i = 0; i < n; i++) { out += t; } return out; }
template<class T> T math_P(T m, T n) { T ret = 1; for (T i = m; i > m - n; i--) { ret *= i; } return ret; }
template<class T> T math_C(T m, T n) { T ret = math_P(m, n); for (T i = 2; i <= n; i++) { ret /= i; } return ret; }
template<class T> bool cmp_2nd(pair<T, T> a, pair<T, T> b) { if (a.second != b.second) { return a.second < b.second; } return a.first < b.first; }
template<class T> T mod_pow(T x, T n, const T& p) { T ret = 1; while (n > 0) { if (n & 1) { (ret *= x) %= p; } (x *= x) %= p; n >>= 1; } return ret; }

/*****/

ll N, M;
vector<pr<ll>> R;

//bool cmp(pr<ll> a, pr<ll> b) { if (a.first != b.first) { return a.first < b.first; } return a.second < b.second; }
//bool eq(pr<ll> a, pr<ll> b) { return a.first == b.first; }

void Main()
{
	cin >> N >> M;
	R.resize(M);
	rep(i, M)
	{
		cin >> R[i].first >> R[i].second;
	}

	sort(all(R), cmp_2nd<ll>);
	/**
	rep(i, M)
	{
		debug("R" + to_string(i));
		debug_tabheadcout(1, "1st", R[i].first);
		debug_tabheadcout(1, "2nd", R[i].second);
	}
	/**/

	/**
	R.erase(unique(all(R), eq), R.end());
	M = R.size();
	/**/

	ll ret = 0;
	ll end = -1;
	rep(i, M)
	{
		if (R[i].first >= end)
		{
			ret++;
			end = R[i].second;
		}
	}

	cout << ret;
}

/*****/

int main()
{
	//std::ios::sync_with_stdio(false);
	//std::cin.tie(0);

	std::cout << std::fixed << std::setprecision(10);

	/*
	while (true)
	{
		Main();
		cout << endl;
	}
	//*/

	Main();
	cout << endl;

	return 0;
}


Measured memory_bytes: 1792