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 Restaurant {
    public static void main(String[] args) {
        FastReader in = new FastReader();
        PrintWriter out = new PrintWriter(new BufferedOutputStream(System.out));

        TreeMap<Integer, Integer> tree = new TreeMap<>();

        int n = in.nextInt();
        for (int i = 0; i < n; i++) {
            int key = in.nextInt();
            int value = in.nextInt();
            tree.put(value, ((tree.containsKey(value)) ? Math.max(key, tree.get(value)) : key));
        }

        int end = Integer.MIN_VALUE;
        int res = 0;
        for (Map.Entry<Integer, Integer> entry : tree.entrySet()) {
            //out.println(entry.getValue() + " " + entry.getKey());
            if (entry.getValue() > end) {
                end = entry.getKey();
                res++;
            }
        }
        out.println(res);
        out.close();
    }

    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        FastReader() {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

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