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 N = 6e5 + 10, Mod = 1e9 + 7;
long long dp[N];
vector<pair<long long, long long>> v(N);
long long n;
long long res(long long i) {
  if (i == n) return 0;
  long long &ans = dp[i];
  if (ans != -1) return ans;
  ans = 1;
  auto y = make_pair(v[i].second + 1, 0LL);
  long long x = lower_bound(v.begin() + i, v.begin() + n, y) - v.begin();
  if (x < n) {
    ans = max(ans, 1 + res(x));
  }
  ans = max(ans, res(i + 1));
  return ans;
}
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  cin >> n;
  memset(dp, -1, sizeof(dp));
  for (long long i = 0; i < n; i++) {
    cin >> v[i].first;
    cin >> v[i].second;
  }
  sort(v.begin(), v.begin() + n);
  cout << res(0);
  return 0;
}
