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
//package CodeForces.TestingRound12;

import java.util.*;

/**
 * Created by ilya on 11.11.15.
 */
public class B597 {

    public static HashMap<Integer, Integer> known = new HashMap<>();

    public static int max(Map.Entry<Integer, Integer> integerIntegerEntry, TreeMap<Integer, Integer> orders){
        if(orders.tailMap(integerIntegerEntry.getValue(), false).size() == 0) return 0;
        else if(orders.tailMap(integerIntegerEntry.getValue(), false).size() == 1) return 1;
        else {
            if(known.containsKey(integerIntegerEntry.getValue())) return known.get(integerIntegerEntry.getValue());
            int tmp = 0, max = 0;
            for (Map.Entry<Integer, Integer> integerIntegerEntry2 : orders.tailMap(integerIntegerEntry.getValue(), false).entrySet()) {
                tmp = max(integerIntegerEntry2, orders) + 1;
                if(max < tmp) max = tmp;
            }
            known.put(integerIntegerEntry.getValue(), max);
            return max;
        }
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        TreeMap<Integer, Integer> orders = new TreeMap<>();
        int a, b;
        for (int i = 0; i < n; i++) {
            a = sc.nextInt();
            b = sc.nextInt();
            if (!orders.containsKey(b)) orders.put(b, a);
            else if(orders.get(b)<a)orders.put(b,a);
        }
        int l = 0, max = 0;
        for (Map.Entry<Integer, Integer> integerIntegerEntry : orders.entrySet()) {
            if(l == 0) {
                l = integerIntegerEntry.getKey();
                max++;
            }
            else if(integerIntegerEntry.getValue() > l){
                l = integerIntegerEntry.getKey();
                max++;
            }
        }
        System.out.println(max);
    }

}
