#include<iostream>
#include<algorithm>
using namespace std;
struct node {
    int start;
    int end;
}a[2000000];
bool compare(node n1, node n2) {
    return n1.start < n2.start;
}
int main() {
    int n, mi, cnt = 0;
    cin >> n;
    for (int i = 1; i <= n; i++)
        cin >> a[i].start >> a[i].end;
    sort(a + 1, a + 1 + n, compare);
    mi = -1;
    for (int i = 1; i <= n; i++) {
        if (a[i].start >= mi) {
            cnt++;
            mi = a[i].end;
        }
    }
    cout << cnt;
}