#include <iostream>
#include <vector>
#include <algorithm>
#include <map>

using namespace std;

int main()
{
    int n, i, j = 0, k, out = 0, temp;
    cin >> n;

	vector<pair<int, int>> intervals(n); //fordított sorrendben experimenting
	map<int, vector<int>> startsat;

	for (i = 0; i < n; i++)
	{
		cin >> intervals[i].second >> intervals[i].first;
	}

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

	for (i = 0; i < n; i++)
	{
		if (startsat.count(intervals[i].second) == 0)
		{
			startsat[intervals[i].second] = { i };
		}
		else
		{
			startsat[intervals[i].second].push_back(i);
		}
	}

	for (i = 0; i < n; i++)
	{
		out++;

		while (intervals[j].second == -1)
		{
			j++;
		}
		intervals[j].second = -1;
		k = intervals[j].first;

		while (startsat[k].size() > 0)
		{
			temp = k;
			k = intervals[startsat[temp].back()].first;
			intervals[startsat[temp].back()].second = -1;
			startsat[temp].pop_back();
			i++;
		}
	}

	cout << out;
}
//4
//4 9
//2 4
//9 12
//1 4