#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].s2;
    for(int i=2;i<=n;i++){
        if(a[i].s1>=e){
            ans++;
            e=a[i].s2;
        }
    }
    cout<<ans;
    return 0;
}
/**************************************************************
	Problem: 1372
	User: wengsihan
	Language: C++
	Result: Accepted
	Time:9 ms
	Memory:2080 kb
****************************************************************/