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;
pair<long long, long long> orderA[500005];
pair<long long, long long> orderB[500005];
void copyArray(int mBegin, int mEnd) {
  for (int i = mBegin; i < mEnd; i++) {
    orderA[i] = orderB[i];
  }
}
void doMerge(int mBegin, int mMid, int mEnd) {
  int i = mBegin, j = mMid;
  for (int k = mBegin; k < mEnd; k++) {
    if (i < mMid && (j >= mEnd || orderA[i].second <= orderA[j].second)) {
      orderB[k] = orderA[i];
      i++;
    } else {
      orderB[k] = orderA[j];
      j++;
    }
  }
}
void splitMerge(int mBegin, int mEnd) {
  if (mEnd - mBegin < 2) return;
  int mMid = (mEnd + mBegin) / 2;
  splitMerge(mBegin, mMid);
  splitMerge(mMid, mEnd);
  doMerge(mBegin, mMid, mEnd);
  copyArray(mBegin, mEnd);
}
void mergeSort(int n) { splitMerge(0, n); }
int main() {
  int N;
  scanf("%d", &N);
  for (int i = 0; i < N; i++) {
    long long x, y;
    scanf("%I64d %I64d", &x, &y);
    orderA[i] = make_pair(x, y);
  }
  mergeSort(N);
  long long current = 0;
  int ans = 0;
  for (int i = 0; i < N; i++) {
    if (current < orderA[i].first) {
      current = orderA[i].second;
      ans++;
    }
  }
  cout << ans << "\n";
  return 0;
}
