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;
vector<pair<int, int> > S;
int dp[1000005];
int rek(int pos) {
  if (pos == n) {
    return 0;
  }
  int &ans = dp[pos];
  if (ans != -1) return ans;
  ans = 1;
  ans = max(ans, rek(pos + 1));
  int nex = lower_bound(S.begin(), S.end(), make_pair(S[pos].second + 1, -1)) -
            S.begin();
  ans = max(ans, rek(nex) + 1);
  return ans;
}
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    int l, r;
    scanf("%d%d", &l, &r);
    S.push_back(make_pair(l, r));
  }
  sort(S.begin(), S.end());
  memset(dp, -1, sizeof(dp));
  printf("%d\n", rek(0));
  return 0;
}
