#include <stdio.h>
#include <queue>
#include <algorithm>
using namespace std;
bool flag[1000005];
priority_queue<int> a;
priority_queue<int> b;
long long int n, ans, p = -1, c[1000005], d;
int main() {
    scanf("%lld", &n);
    for (int i = 1; i <= n; ++i) {
        scanf("%lld%lld", &c[i], &d);
        a.push(c[i]);
        b.push(d);
    }
    sort(c + 1, c + n + 1);
    for (int i = 1; i <= n; ++i) {
        if (p <= a.top && flag[i] == 0) {
            for (int j = 1; j <= n; ++j) {
                if (flag[j] == 0 && b.top >= c[i])
                    flag[j] = 1;
            }
            p = b.top();
            ans++;
        }
        a.pop();
        b.pop();
    }
    printf("%lld", ans);
    return 0;
}

/sandbox/1/a.cpp: In function 'int main()':
/sandbox/1/a.cpp:21:11: error: invalid use of member function 'std::priority_queue<_Tp, _Sequence, _Compare>::const_reference std::priority_queue<_Tp, _Sequence, _Compare>::top() const [with _Tp = int; _Sequence = std::vector<int, std::allocator<int> >; _Compare = std::less<int>; std::priority_queue<_Tp, _Sequence, _Compare>::const_reference = const int&]' (did you forget the '()' ?)
   21 |   if(p<=a.top&&flag[i]==0)
      |         ~~^~~
      |              ()
/sandbox/1/a.cpp:25:22: error: invalid use of member function 'std::priority_queue<_Tp, _Sequence, _Compare>::const_reference std::priority_queue<_Tp, _Sequence, _Compare>::top() const [with _Tp = int; _Sequence = std::vector<int, std::allocator<int> >; _Compare = std::less<int>; std::priority_queue<_Tp, _Sequence, _Compare>::const_reference = const int&]' (did you forget the '()' ?)
   25 |     if(flag[j]==0&&b.top>=c[i])
      |                    ~~^~~
      |                         ()
/sandbox/1/a.cpp:11:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   11 |  scanf("%lld",&n);
      |  ~~~~~^~~~~~~~~~~
/sandbox/1/a.cpp:14:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   14 |   scanf("%lld%lld",&c[i],&d);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~