#include <iostream>
#include <algorithm>
#define x first
#define y second
using namespace std;

typedef pair<int, int> PII;
const int N = 100010;

PII q[N];
bool cmp(PII a, PII b)
{
    return a.y < b.y;
}
int main()
{
    int n;
    scanf("%d", &n);
    int a, b;
    for(int i = 0; i < n; i ++)
    {
        cin >> a >> b;
        q[i].x = a;
        q[i].y = b;
        // cout << q[i].x << " " << q[i].y << endl;
    }
    sort(q, q + n, cmp);
    int ans = 0, t = 9e9;
    for(int i = 0; i < n; i ++)
    {
        // cout << t << endl;
        if(t >= q[i].x && t <= q[i].y) continue;
        else
        {
            t = q[i].y;
            ans ++;
        }

    }
    printf("%d", ans);
}