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;
int n, ans;
pair<int, int> p[500001];
bool cmp(const pair<int, int> &lhs, const pair<int, int> &rhs) {
  if (lhs.second == rhs.second) return lhs.first < rhs.first;
  return lhs.second < rhs.second;
}
int main() {
  std::ios::sync_with_stdio(false);
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) scanf("%d %d", &p[i].first, &p[i].second);
  sort(p + 1, p + 1 + n, cmp);
  int prev = -1e9;
  for (int i = 1; i <= n; i++)
    if (p[i].first > prev) prev = p[i].second, ans++;
  printf("%d\n", ans);
  return 0;
}
