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 long long mod = 998244353;
inline void solve() {
  long long n;
  cin >> n;
  vector<pair<long long, long long> > v(n);
  for (long long i = 0; i < n; i++) cin >> v[i].second >> v[i].first;
  sort(v.begin(), v.end());
  long long ans = 0, pre = 0;
  for (long long i = 0; i < n; i++) {
    if (v[i].second > pre) {
      ans++;
      pre = v[i].first;
    }
  }
  cout << ans << '\n';
}
signed main() {
  long long n = 1;
  while (n--) solve();
  return 0;
}
