#include <bits/stdc++.h>
using namespace std;

const int N = 2e5+10;

struct node{
	int l,r;
}a[N];

bool cmp(node x,node y){
	if(x.l==y.l)return x.r>y.r;
	return x.l<y.l;
} 

int n,m,tot,pos_r;

int main(){
	freopen("bridge.in","r",stdin);
	freopen("bridge.out","w",stdout);
	scanf("%d%d",&n,&m);
	for(int i=1;i<=m;i++){
		scanf("%d%d",&a[i].l,&a[i].r);
	} 
	sort(a+1,a+1+m,cmp);
	for(int i=1;i<=m;i++){
		if(pos_r<=a[i].l){
			tot++;
			pos_r=a[i].r;
		}else{
			pos_r=min(pos_r,a[i].r);
		}
	}
	printf("%d",tot);
	return 0;
}