A restaurant received n orders for the rental. Each rental order reserve the restaurant for a continuous period of time, the i-th order is characterized by two time values — the start time li and the finish time ri (li ≤ ri).

Restaurant management can accept and reject orders. What is the maximal number of orders the restaurant can accept?

No two accepted orders can intersect, i.e. they can't share even a moment of time. If one order ends in the moment other starts, they can't be accepted both.

Input

The first line contains integer number n (1 ≤ n ≤ 5·105) — number of orders. The following n lines contain integer values li and ri each (1 ≤ li ≤ ri ≤ 109).

Output

Print the maximal number of orders that can be accepted.

Examples

Input

2
7 11
4 7


Output

1


Input

5
1 2
2 3
3 4
4 5
5 6


Output

3


Input

6
4 8
1 5
4 7
2 5
1 3
6 8


Output

2
import java.io.BufferedReader;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Map;
import java.util.Set;
import java.util.StringTokenizer;

public class B {
	
	public static class Range implements Comparable<Range>{
		long start, last;
		
		public Range(long start, long last){
			this.start = start;
			this.last = last;
		}

		@Override
		public int compareTo(Range arg0) {
			if(Long.compare(this.last, arg0.last) != 0){
				return Long.compare(this.last, arg0.last);
			}else{
				return -Long.compare(this.start, arg0.start);
			}
		}
		
		@Override
		public String toString(){
			return "[" + this.start + ", " + this.last + "]";
		}
	}
	
	public static void main(String[] args) {
		try (final Scanner sc = new Scanner(System.in)) {
			final int n = sc.nextInt();
			
			Range[] array = new Range[n];
			for(int i = 0; i < n; i++){
				final long l = sc.nextLong();
				final long r = sc.nextLong();
				
				array[i] = new Range(l, r);
			}
			
			Arrays.sort(array);
			
			int answer = 0;
			long last = 0;
			for(int i = 0; i < n; i++){
				if(last < array[i].start){
					//System.out.println(array[i]);
					last = array[i].last;
					answer++;
				}
			}
			
			System.out.println(answer);
		}
	}

	public static class Scanner implements Closeable {
		private BufferedReader br;
		private StringTokenizer tok;

		public Scanner(InputStream is) {
			br = new BufferedReader(new InputStreamReader(is));
		}

		private void getLine() {
			try {
				while (!hasNext()) {
					tok = new StringTokenizer(br.readLine());
				}
			} catch (IOException e) { /* ignore */
			}
		}

		private boolean hasNext() {
			return tok != null && tok.hasMoreTokens();
		}

		public String next() {
			getLine();
			return tok.nextToken();
		}

		public int nextInt() {
			return Integer.parseInt(next());
		}

		public long nextLong() {
			return Long.parseLong(next());
		}

		public void close() {
			try {
				br.close();
			} catch (IOException e) { /* ignore */
			}
		}
	}
}
