import std.stdio, std.string, std.conv;
import std.range, std.algorithm, std.array, std.typecons, std.container;
import std.math, std.numeric, core.bitop;

alias Seg = Tuple!(int, "l", int, "r");

void main() {
    int n, m;
    scan(n, m);

    auto ss = new Seg[](m);

    foreach (i ; 0 .. m) {
        int ai, bi;
        scan(ai, bi);
        ss[i] = Seg(ai, bi);
    }

    ss.sort!"a.r < b.r"();

    int ans;
    int x = -1000000;

    foreach (i ; 0 .. m) {
        if (ss[i].l < x) {
            continue;
        }
        else {
            ans++;
            x = ss[i].r;
        }
    }

    writeln(ans);
}









































void scan(T...)(ref T args) {
    import std.stdio : readln;
    import std.algorithm : splitter;
    import std.conv : to;
    import std.range.primitives;

    auto line = readln().splitter();
    foreach (ref arg; args) {
        arg = line.front.to!(typeof(arg));
        line.popFront();
    }
    assert(line.empty);
}



void fillAll(R, T)(ref R arr, T value) {
    static if (is(typeof(arr[] = value))) {
        arr[] = value;
    }
    else {
        foreach (ref e; arr) {
            fillAll(e, value);
        }
    }
}
