#include <stdio.h>
#include <algorithm>
using namespace std;
struct map {
    int no, go, h;
    bool end;
} a[1000005];
long long int n, ans, p = -1;
bool cmp(map a, map b) { return a.go < b.go; }
int main() {
    scanf("%lld", &n);
    for (int i = 1; i <= n; ++i) {
        scanf("%lld%lld", &a[i].no, &a[i].go);
    }
    sort(a + 1, a + n + 1, cmp);
    for (int i = 1; i <= n; ++i) {
        if (p <= a[i].no && a[i].end == 0) {
            for (int j = 1; j <= n; ++j) {
                if (a[j].end == 0 && a[i].go >= a[j].no)
                    a[j].end = 1;
            }
            p = a[i].go;
            ans++;
        }
    }
    printf("%lld", ans);
    return 0;
}