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;
long long n;
vector<pair<long long, long long> > v;
long long dp[500005];
long long find(long long idx, long long l) {
  if (idx < 0) return 0;
  if (dp[idx] != -1) return dp[idx];
  if (v[idx].second < l)
    dp[idx] = max(dp[idx], 1 + find(idx - 1, v[idx].first));
  dp[idx] = max(dp[idx], find(idx - 1, l));
  return dp[idx];
}
void solve() {
  cin >> n;
  for (long long i = 0; i < n; ++i) {
    long long l, r;
    cin >> l >> r;
    v.push_back({l, r});
  }
  sort(v.begin(), v.end());
  memset(dp, -1, sizeof dp);
  cout << find(n - 1, 2e9) << '\n';
}
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  srand(static_cast<unsigned>(time(0)));
  long long t = 1;
  while (t--) {
    solve();
  }
  return 0;
}
