#include <iostream>
#include <algorithm>
#include <cstring>
#include <vector>
using namespace std;
const int N = 1e6 + 10;

int n;

bool cmp(vector<int> x, vector<int> y)
{
    return x[1] < y[1];
}

int main()
{
    cin >> n;
    vector<vector<int>> a(n);
    for(int i = 0; i < n; i ++) 
    {
    	int x, y;
    	cin >> x >> y;
    	a[i].push_back(x);
    	a[i].push_back(y);
    }

    sort(a.begin(), a.end(), cmp);
    
    int res = 0, ed = -2e9;
    for(int i = 0; i < n; i ++)
    {
        if(ed <= a[i][0])
        {
        	res ++;
            ed = a[i][1];
        }
    }
    
    cout << res << endl;
    
    return 0;
}