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

/sandbox/1/a.cpp: In function 'int main()':
/sandbox/1/a.cpp:23:18: error: reference to 'end' is ambiguous
   23 |   if(p<=a[i].no&&end[i]==0)
      |                  ^~~
In file included from /usr/include/c++/10/array:41,
                 from /usr/include/c++/10/tuple:39,
                 from /usr/include/c++/10/functional:54,
                 from /usr/include/c++/10/pstl/glue_algorithm_defs.h:13,
                 from /usr/include/c++/10/algorithm:74,
                 from /sandbox/1/a.cpp:2:
/usr/include/c++/10/bits/range_access.h:110:37: note: candidates are: 'template<class _Tp> const _Tp* std::end(const std::valarray<_Tp>&)'
  110 |   template<typename _Tp> const _Tp* end(const valarray<_Tp>&);
      |                                     ^~~
/usr/include/c++/10/bits/range_access.h:109:31: note:                 'template<class _Tp> _Tp* std::end(std::valarray<_Tp>&)'
  109 |   template<typename _Tp> _Tp* end(valarray<_Tp>&);
      |                               ^~~
/usr/include/c++/10/bits/range_access.h:100:5: note:                 'template<class _Tp, unsigned int _Nm> constexpr _Tp* std::end(_Tp (&)[_Nm])'
  100 |     end(_Tp (&__arr)[_Nm])
      |     ^~~
/usr/include/c++/10/bits/range_access.h:81:5: note:                 'template<class _Container> constexpr decltype (__cont.end()) std::end(const _Container&)'
   81 |     end(const _Container& __cont) -> decltype(__cont.end())
      |     ^~~
/usr/include/c++/10/bits/range_access.h:71:5: note:                 'template<class _Container> constexpr decltype (__cont.end()) std::end(_Container&)'
   71 |     end(_Container& __cont) -> decltype(__cont.end())
      |     ^~~
In file included from /usr/include/c++/10/utility:76,
                 from /usr/include/c++/10/algorithm:60,
                 from /sandbox/1/a.cpp:2:
/usr/include/c++/10/initializer_list:101:5: note:                 'template<class _Tp> constexpr const _Tp* std::end(std::initializer_list<_Tp>)'
  101 |     end(initializer_list<_Tp> __ils) noexcept
      |     ^~~
/sandbox/1/a.cpp:8:6: note:                 'bool end [1000005]'
    8 | bool end[1000005];
      |      ^~~
/sandbox/1/a.cpp:27:8: error: reference to 'end' is ambiguous
   27 |     if(end[j]==0&&a[i].go>=a[j].no)
      |        ^~~
In file included from /usr/include/c++/10/array:41,
                 from /usr/include/c++/10/tuple:39,
                 from /usr/include/c++/10/functional:54,
                 from /usr/include/c++/10/pstl/glue_algorithm_defs.h:13,
                 from /usr/include/c++/10/algorithm:74,
                 from /sandbox/1/a.cpp:2:
/usr/include/c++/10/bits/range_access.h:110:37: note: candidates are: 'template<class _Tp> const _Tp* std::end(const std::valarray<_Tp>&)'
  110 |   template<typename _Tp> const _Tp* end(const valarray<_Tp>&);
      |                                     ^~~
/usr/include/c++/10/bits/range_access.h:109:31: note:                 'template<class _Tp> _Tp* std::end(std::valarray<_Tp>&)'
  109 |   template<typename _Tp> _Tp* end(valarray<_Tp>&);
      |                               ^~~
/usr/include/c++/10/bits/range_access.h:100:5: note:                 'template<class _Tp, unsigned int _Nm> constexpr _Tp* std::end(_Tp (&)[_Nm])'
  100 |     end(_Tp (&__arr)[_Nm])
      |     ^~~
/usr/include/c++/10/bits/range_access.h:81:5: note:                 'template<class _Container> constexpr decltype (__cont.end()) std::end(const _Container&)'
   81 |     end(const _Container& __cont) -> decltype(__cont.end())
      |     ^~~
/usr/include/c++/10/bits/range_access.h:71:5: note:                 'template<class _Container> constexpr decltype (__cont.end()) std::end(_Container&)'
   71 |     end(_Container& __cont) -> decltype(__cont.end())
      |     ^~~
In file included from /usr/include/c++/10/utility:76,
                 from /usr/include/c++/10/algorithm:60,
                 from /sandbox/1/a.cpp:2:
/usr/include/c++/10/initializer_list:101:5: note:                 'template<class _Tp> constexpr const _Tp* std::end(std::initializer_list<_Tp>)'
  101 |     end(initializer_list<_Tp> __ils) noexcept
      |     ^~~
/sandbox/1/a.cpp:8:6: note:                 'bool end [1000005]'
    8 | bool end[1000005];
      |      ^~~
/sandbox/1/a.cpp:28:5: error: reference to 'end' is ambiguous
   28 |     end[j]=1;
      |     ^~~
In file included from /usr/include/c++/10/array:41,
                 from /usr/include/c++/10/tuple:39,
                 from /usr/include/c++/10/functional:54,
                 from /usr/include/c++/10/pstl/glue_algorithm_defs.h:13,
                 from /usr/include/c++/10/algorithm:74,
                 from /sandbox/1/a.cpp:2:
/usr/include/c++/10/bits/range_access.h:110:37: note: candidates are: 'template<class _Tp> const _Tp* std::end(const std::valarray<_Tp>&)'
  110 |   template<typename _Tp> const _Tp* end(const valarray<_Tp>&);
      |                                     ^~~
/usr/include/c++/10/bits/range_access.h:109:31: note:                 'template<class _Tp> _Tp* std::end(std::valarray<_Tp>&)'
  109 |   template<typename _Tp> _Tp* end(valarray<_Tp>&);
      |                               ^~~
/usr/include/c++/10/bits/range_access.h:100:5: note:                 'template<class _Tp, unsigned int _Nm> constexpr _Tp* std::end(_Tp (&)[_Nm])'
  100 |     end(_Tp (&__arr)[_Nm])
      |     ^~~
/usr/include/c++/10/bits/range_access.h:81:5: note:                 'template<class _Container> constexpr decltype (__cont.end()) std::end(const _Container&)'
   81 |     end(const _Container& __cont) -> decltype(__cont.end())
      |     ^~~
/usr/include/c++/10/bits/range_access.h:71:5: note:                 'template<class _Container> constexpr decltype (__cont.end()) std::end(_Container&)'
   71 |     end(_Container& __cont) -> decltype(__cont.end())
      |     ^~~
In file included from /usr/include/c++/10/utility:76,
                 from /usr/include/c++/10/algorithm:60,
                 from /sandbox/1/a.cpp:2:
/usr/include/c++/10/initializer_list:101:5: note:                 'template<class _Tp> constexpr const _Tp* std::end(std::initializer_list<_Tp>)'
  101 |     end(initializer_list<_Tp> __ils) noexcept
      |     ^~~
/sandbox/1/a.cpp:8:6: note:                 'bool end [1000005]'
    8 | bool end[1000005];
      |      ^~~
/sandbox/1/a.cpp:34:13: warning: format '%lld' expects argument of type 'long long int', but argument 2 has type 'int' [-Wformat=]
   34 |  printf("%lld",ans);
      |          ~~~^  ~~~
      |             |  |
      |             |  int
      |             long long int
      |          %d
/sandbox/1/a.cpp:15:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 |  scanf("%d",&n);
      |  ~~~~~^~~~~~~~~
/sandbox/1/a.cpp:18:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   18 |   scanf("%d%d",&a[i].no,&a[i].go);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~