#include<bits/stdc++.h>

using namespace std;

const int N = 100005;

typedef pair<int, int> PII;

PII p[N];

bool cmp(PII a, PII b){
    return a.second < b.second;
}

int main(){
    int n, cnt = 0;
    cin>>n;
    for(int i = 0; i < n; i++){
        cin>>p[i].first>>p[i].second;
    }
    sort(p, p + n, cmp);
    for(int i = 0, ed = -2e9; i < n; i++){
        int l = p[i].first, r = p[i].second;
        if(l > ed){
            cnt++;
            ed = r;
        }
    }
    cout<<cnt<<endl;
    return 0;
}