#include<bits/stdc++.h>
using namespace std;
const int MAXN=2e5+5;
int n,m;
priority_queue<pair<int,int> >que;
int ans=1,k;
int main(){
    freopen("bridge.in","r",stdin);
    freopen("bridge.out","w",stdout);
    cin>>n>>m;
    for(int i=1;i<=m;i++){
        int a,b;
        cin>>a>>b;
        que.push(make_pair(-b,-a));
    }
    int k=-que.top().first;
    que.pop();
    while(!que.empty()){
        int x=-que.top().second;
        if(k>x){
            que.pop();
        }else {
            k=-que.top().first;
            ans++;
            que.pop();
        }
    }
    cout<<ans<<endl;
    return 0;
}