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 = 5 * 1e5 + 10;
int dp[maxn][2];
pair<int, int> orders[maxn];
bool cmp(pair<int, int> &a, pair<int, int> &b) {
  if (a.second != b.second) return a.second < b.second;
  return a.first < b.first;
}
int main() {
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) cin >> orders[i].first >> orders[i].second;
  sort(orders, orders + n, cmp);
  dp[0][1] = 1;
  dp[0][0] = 0;
  int ans = dp[0][1];
  for (int i = 1; i < n; i++) {
    dp[i][0] = max(dp[i - 1][0], dp[i - 1][1]);
    int l = 0;
    int r = i - 1;
    int tmp = -1;
    while (l <= r) {
      int mid = (l + r) >> 1;
      if (orders[mid].second < orders[i].first) {
        dp[i][1] = max(dp[i][1], max(dp[mid][0], dp[mid][1]) + 1);
        l = mid + 1;
      } else
        r = mid - 1;
    }
    ans = max(ans, max(dp[i][0], dp[i][1]));
  }
  cout << ans << endl;
  return 0;
}
