/*
 * @Author: YMYS
 * @Date: 2024-01-25 17:04:07
 * @LastEditTime: 2025-04-05 18:25:15
 * @FilePath: \VScode-C&C++-Coding\Acwing\算法基础课\1.第一章\9.区间合并\练手.cpp
 * @URL:https://www.acwing.com/problem/content/805/
 * @Description: 803. 区间合并
 * 
 * 贪心
 * 
 */
#include<bits/stdc++.h>

#define int long long
#define err cout << "error" << endl

using namespace std;

const int N = 1e5 +10;

// int T;
// void solve(){

// }

int n;
vector<pair<int, int>> vc;
vector<pair<int, int>> xx;

signed main()
{
#ifdef ABC
    freopen("D:/daily_Coding/VScode-C&C++-Coding/in.in", "r", stdin);
    freopen("D:/daily_Coding/VScode-C&C++-Coding/out.out", "w", stdout);
#endif
    std::ios::sync_with_stdio(false);cin.tie(0); cout.tie(0);

    // cin>>T;
    // while(T--){
    //     solve();
    // }
    cin>>n;
    for(int i=0;i<n;i++){
        int l,r;
        cin>>l>>r;
        vc.push_back({l,r});
    }

    sort(vc.begin(), vc.end());

    int l = -2e9, r = -2e9;
    for(auto it : vc){
        int t = it.first;
        if(t>r){
            if(l != -2e9) xx.push_back({l,r});//放入上一条线段
            l = it.first;
            r = it.second;
        }else{
            r = max(r, it.second);
        }
    }

    if(l!=-2e9) xx.push_back({l,r});

    cout<<xx.size()<<endl;

    return 0;
}