#include <stdio.h>
#include <algorithm>
using namespace std;
int p, ans;
struct sai {
    long go, end;
    bool flag;
} a[1000005];
bool cmp(sai a, sai b) { return a.end < b.end; }
int main() {
    int n;
    scanf("%lld", &n);
    for (int i = 0; i < n; i++) {
        scanf("%lld %lld", &a[i].go, &a[i].end);
    }
    sort(a, a + n, cmp);
    for (int i = 0; i < n; i++) {
        if (p <= a[i].go && a[i].flag == 0) {
            for (int j = 0; j < n; j++) {
                if (a[j].flag == 0 && a[i].end >= a[j].go)
                    a[j].flag = 1;
            }
            p = a[i].end;
            ans++;
        }
    }
    printf("%d\n", ans);
    return 0;
}