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.*;
import java.util.*;
public class Solution
{
    public static void main(String ag[])
    {
        Scanner sc=new Scanner(System.in);
        int i,j,k;
        int N=sc.nextInt();
        Pair A[]=new Pair[N];
        for(i=0;i<N;i++)
        {
            A[i]=new Pair(sc.nextInt(),sc.nextInt());
        }
        Arrays.sort(A);
        int ans=0;
        int end=0;
        for(i=0;i<N;i++)
        {
            if(A[i].s>end)
            {
                end=A[i].e;
                ans++;
            }
        }
        System.out.println(ans);
    }
}
class Pair implements Comparable<Pair>
{
    int s,e;
    Pair(int p,int q)
    {
        s=p;
        e=q;
    }
    public int compareTo(Pair P)
    {
        return this.e-P.e;
    }
}