#include<bits/stdc++.h>
using namespace std;
int n,ans,nowend; 
struct Node{
	int begin,end;
}a[105];
bool cmp(Node x,Node y){
	return x.end<y.end;
}
int main(){
	cin>>n;
	for(int i=1;i<=n;i++) cin>>a[i].begin>>a[i].end;
	sort(a+1,a+n+1,cmp);
	ans=1;
	nowend=a[1].end;
	for(int i=2;i<=n;i++){
		if(a[i].begin>=nowend){
			ans++;
            nowend=a[i].end;
		}
	}
	cout>>ans;

    return 0;
}

/**************************************************************
	Problem: 1372
	User: caijiajie
	Language: C++
	Result: Compile Error
****************************************************************/