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
#include <bits/stdc++.h>
using namespace std;
const int maxn = 1000000 + 10;
const int INF = 999999999;
struct Order {
  int st;
  int ed;
} ord[maxn];
Order flow[maxn];
bool cmp(const Order& a, const Order& b) { return a.ed < b.ed; }
int main() {
  int n;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%d%d", &ord[i].st, &ord[i].ed);
  }
  sort(ord, ord + n, cmp);
  flow[0] = ord[0];
  int k = 1;
  for (int i = 1; i < n; i++) {
    if (flow[k - 1].ed < ord[i].st) {
      flow[k++] = ord[i];
    }
  }
  cout << k << endl;
}
