//
//
//  Codeforces: ganariya
//  AtCoder: ganariya2525
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//  MMMMMMMMMMMMMMMMNOtXtdMMMMMNxzZMMNmgHyVVVVVW%..?/(.,(x-..........(HfffpffpffpffWHHffpffppfVyyWMMMMMM


//include
//------------------------------------------
#include <vector>
#include <list>
#include <map>
#include <unordered_map>
#include <climits>
#include <set>
#include <unordered_set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <queue>
#include <random>
#include <complex>
#include <regex>
#include <locale>
#include <random>
#include <type_traits>

using namespace std;

#define SHOW_VECTOR(v) {std::cerr << #v << "\t:";for(const auto& xxx : v){std::cerr << xxx << " ";}std::cerr << "\n";}
#define SHOW_MAP(v){std::cerr << #v << endl; for(const auto& xxx: v){std::cerr << xxx.first << " " << xxx.second << "\n";}}

using LL = long long;

//~~~~~~~~~~~~~~~~~~~~~_(＾～＾ ｣ ∠)_~~~~~~~~~~~~~~~~~~~~~

int main() {

    int n, m;
    cin >> n >> m;

    vector<int> x(m), y(m);
    for (int i = 0; i < m; i++) cin >> x[i] >> y[i];

    vector<pair<int, int>> xy(m);
    for (int i = 0; i < m; i++) xy[i] = make_pair(x[i], y[i]);

    sort(xy.begin(), xy.end(), [](const auto &a, const auto &b) {
        return a.second < b.second;
    });

    int ans = 0;
    pair<int, int> p(-1, -1);
    for (int i = 0; i < m; i++) {
        if (p == make_pair(-1, -1)) {
            ans++;
            p = xy[i];
            continue;
        }
        if (xy[i].first < p.second) continue;
        p = xy[i];
        ans++;
    }

    cout << ans;

    return 0;
}
















































Measured memory_bytes: 1792