#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;

const int N=100000+1;

struct info {
    int st,dr;
};

int len,n;
info v[N];
bool cmp(info a,info b) {
    if(a.st==b.st)
        return a.dr>b.dr;
    return a.st<b.st;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cin>>len>>n;
    for(int i=1;i<=n;i++) {
        cin>>v[i].st>>v[i].dr;
    }
    sort(v+1,v+n+1,cmp);
    int ans=1;
    int st=v[1].st;
    int dr=v[1].dr;
    for(int i=2;i<=n;i++) {
        if(v[i].st>=dr) {
            ans++;
            dr=v[i].dr;
        }
        dr=min(dr,v[i].dr);
    }
    cout<<ans<<"\n";
    return 0;
}
/**

0 0 0 0


**/