文件目录

#include <bits/stdc++.h>
using namespace std;
struct node
{
    int bt;
    int et;
    bool operator<(const node &b) const
    {
        return et < b.et;
    }
} a[1005];
int n;
int main()
{
    cin >> n;
    for (int i = 1; i <= n; i++)
        cin >> a[i].bt >> a[i].et;
    sort(a + 1, a + 1 + n);
    int ans = 0, ti = 0;
    for (int i = 1; i <= n; i++)
        if (a[i].bt >= ti)
        {
            ans++;
            ti = a[i].et;
        }

    cout << ans;
    return 0;
}