#include<bits/stdc++.h>
using namespace std;
struct node{
    int begin,end;
}a[101];
bool cmp(node x,node y)
{
    return x.end<y.end;
}
int n,nowend,ans;
int main(){
    cin>>n;
    for(int i=1;i<=n;i++)
    {
        cin>>a[i].begin>>a[i].end;
    }
    sort(a+1,a+1+n,cmp);
    nowend=a[1].end;
    for(int i=2;i<=n;i++)
    {
        if(a[i].begin>=nowend){
            ans++;
            nowend=a[i].end;
        }
    }
    cout<<ans+1;
}
/**************************************************************
	Problem: 1372
	User: zhengyuxuan
	Language: C++
	Result: Accepted
	Time:9 ms
	Memory:2076 kb
****************************************************************/