#include < iostream >
using   namespace  std;

struct  arr{
     int  x,y;
}a[ 100001 ];
int  N,M;
int  f[ 30005 ];
int  cmp( const   void *  no1, const   void *  no2){
     return  ( * (arr * )no1).x - ( * (arr * )no2).x;
}
int  main()
{
    scanf( " %d " , & N);
    M = 0 ;
     for ( int  i = 1 ;i <= N; ++ i){
        scanf( " %d%d " , & a[i].x, & a[i].y);
         if (M < a[i].x) M = a[i].x;
         if (M < a[i].y) M = a[i].y;
    }
    qsort(a + 1 ,N, sizeof (arr),cmp);
    f[M + 1 ] = 0 ;
     for ( int  i = M;i >= 1 ; -- i){
        f[i] = f[i + 1 ];
         while (i == a[N].x){
             if (f[i] < f[a[N].y + 1 ] + 1 )
                f[i] = f[a[N].y + 1 ] + 1 ;
            N -- ;
        }
    }
    printf( " %d\n " ,f[ 1 ]);
     return   0 ;
}