{

public static void main( String[] args )

{

Scanner s = new Scanner( System.in );

int n = s.nextInt();

int[][] intervals = new int[ n ][ 2 ];

for( int i = 0; i < n; i++ )

{

intervals[i][0] = s.nextInt();

intervals[i][1] = s.nextInt();

}

int minNumberOfRooms = getMinimumNumberOfMeetingRooms( intervals );

System.out.println( minNumberOfRooms );

}

private static int getMinimumNumberOfMeetingRooms( int[][] intervals )

{

if( intervals == null || intervals.length == 0 )

return 0;

Arrays.sort( intervals, ( a, b ) -> a[0] - b[0] );

PriorityQueue<int[]> minHeap = new PriorityQueue<int[]>( ( a, b ) -> a[1] - b[1] );

minHeap.add( intervals[0] );

for(int i=1;i<intervals.length;i++)

{

int[] currentTime = intervals[i];

int[] earliestTime = minHeap.remove();

if(currentTime[0]>=earliestTime[1])

earliestTime[1] = currentTime[1];

else

minHeap.add( currentTime );

minHeap.add( earliestTime );

}

return minHeap.size();

}