#include <iostream>
#include <cstring>
#include <algorithm>
#include <vector>
using namespace std;
typedef pair<int, int> PII;
const int N = 1e5+10;
int n;
vector<PII> segs;
void merge(vector<PII> &segs){
    vector<PII> res;
    sort(segs.begin(),segs.end());
    int st=-2e9,ed=-2e9;
    for(auto seg:segs){
        if(ed<seg.first){//第1和第2个区间无法合并，更新st,ed为第2个区间
            if(st!=-2e9) res.push_back({st,ed});
            st=seg.first,ed=seg.second;
        }else ed=max(ed,seg.second);     //可以合并的合并 
    }
    if(st!=-2e9) res.push_back({st,ed});
    segs=res;
}
int main()
{
    cin >> n;
    for (int i = 0; i < n; i ++ ){
        int l,r;
        cin >> l >>r;
        segs.push_back({l,r});
    }
    merge(segs);
    cout << segs.size() <<endl;

    return 0;
}