#include<bits/stdc++.h>
using namespace std;
const int N=200005;
int a,b,n,m;
pair<int,int> pi[N];
int main(){
	freopen("bridge.in","r",stdin);
	freopen("bridge.out","w",stdout);
	cin>>n>>m;
	for(int i=1;i<=m;i++){
		cin>>pi[i].first>>pi[i].second;
	}
	sort(pi+1,pi+1+m);
	int st,ed;
	st=pi[1].first,ed=pi[1].second;
	int ans=0;
	for(int i=2;i<=m;i++){
		if(pi[i].first<ed){
//			ans++;
			st=pi[i].first;
			ed=min(ed,pi[i].second);
		}
		if(pi[i].first>=ed){
			ans++;
			st=pi[i].first;
			ed=pi[i].second;			
		}
	}
	cout<<ans+1;
	return 0;
}