#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
using namespace std;
int ans, last, n;
struct node {
    int a, b;
} a[1000010];
int cmp(node a, node b) { return a.a < b.a || a.a == b.a && a.b < b.b; }
int main() {
    scanf("%d", &n);
    for (int i = 1; i <= n; i++) scanf("%d%d", &a[i].a, &a[i].b);
    sort(a + 1, a + n + 1, cmp);
    last = 0;
    for (int i = 1; i <= n; i++) {
        if (a[i].a > last) {
            ans++;
            last = a[i].b;
        } else {
            if (a[i].b < last)
                last = a[i].b;
        }
    }
    printf("%d\n", ans);
}

/sandbox/1/a.cpp: In function 'int main()':
/sandbox/1/a.cpp:20:2: error: 'sort' was not declared in this scope
  sort(a+1,a+n+1,cmp);
  ^~~~
/sandbox/1/a.cpp:20:2: note: suggested alternative: 'qsort'
  sort(a+1,a+n+1,cmp);
  ^~~~
  qsort
/sandbox/1/a.cpp:17:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &n);
  ~~~~~^~~~~~~~~~
/sandbox/1/a.cpp:19:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &a[i].a, &a[i].b);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~