#include <iostream>
#include <cstring>
#include <algorithm>

#define x first
#define y second

using namespace std;

typedef pair<int, int> PII;

const int N = 100010;

PII w[N];
int n;

int main(){
    cin >> n;
    for(int i = 0; i < n; i++) cin >> w[i].y >> w[i].x;

    sort(w, w + n);

    int cnt = 0, last = -0x3f3f3f3f;
    for(int i = 0; i < n; i++)
        if(w[i].y > last){
            cnt ++;
            last = w[i].x;
        } 

    cout << cnt << endl;

    return 0;
}