#include<bits/stdc++.h>
using namespace std;
struct w{
	int s1;
	int s2;
}a[200];
bool cmp(w x,w y){
	return x.s2<y.s2;
}
int main(){
    int n;
    cin>>n;
    for(int i=1;i<=n;i++){
    	cin>>a[i].s1>>a[i].s2;
    }
    sort(a+1,a+1+n,cmp);
    int ans=1,e=a[1].y
    for(int i=2;i<=n;i++){
    	if(a[i].x>=e){
    		ans++;
			e=a[i].y
    	}
    }
    cout<<ans;
    return 0;
}

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