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

struct node {
	ll pos,type,id;
	bool operator<(node b)const {
		return id<b.id;
	}
} nodes[2005];
ll cnter=0,vis[2005],qwq[2005];

int main() {
	ll n,m;
	cin >> n >> m;
	for (ll i=1; i<=m; i++) {
		ll f,t;
		cin >> f >> t;
		nodes[++cnter]= {f,1,i};
		nodes[++cnter]= {t,0,i};
	}
	sort(nodes+1,nodes+cnter+1,[](node a,node b) {
		if (a.type==0&&b.type==0)
		return (a.pos==b.pos?a.id<b.id:a.pos<b.pos);
		else
		return (a.pos==b.pos?a.id>b.id:a.pos<b.pos);
	});
	priority_queue<node> pq;
	for (ll i=1; i<=cnter; i++) {
		if (nodes[i].type==1) {
			pq.push(nodes[i]);
		}
		node tp= {0,0,0};
		if (!pq.empty())
			tp=pq.top();
		while (!pq.empty()&&qwq[tp.id]) {
			pq.pop();
			tp=pq.top();
		}
		if (!qwq[tp.id]&&(abs(tp.pos-nodes[i].pos)>=1||tp.id==nodes[i].id))
			vis[tp.id]=1;
//		cout << tp.id << " "<< nodes[i].pos << endl;
		if (nodes[i].type==0) {
			qwq[nodes[i].id]=1;
		}
	}
	ll cnt=0;
	for (ll i=1; i<=m; i++)if (vis[i])cnt++;
	cout << cnt;
	return 0;
}