#include <bits/stdc++.h>
using namespace std;

const int N = 1e5 + 10;

typedef pair<int, int> PII;

vector<PII> p;


int main()
{
    int m;
    cin >> m;

    ios::sync_with_stdio(false);
    cin.tie(0);

    if(m == 0) {cout << 0; return 0;}

    for(int i = 0; i < m; i ++ )
    {
        int l, r;
        cin >> l >> r;
        p.push_back({l,r});
    }

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

    int res = 1, l = p[0].first, r = p[0].second;

    for(int i = 1; i < m; i ++ )
    {
        if(p[i].first > r)
        {
            res ++ ;
            l = p[i].first;
            r = p[i].second;
        }
        else if(p[i].second > r) r = p[i].second;
    }

    cout << res;
    return 0;
}