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>
#pragma comment(linker, "/STACK:320000000")
using namespace std;
const double EPS = 1e-9;
const int INF = 0x7f7f7f7f;
const double PI = acos(-1.0);
template <class T>
inline T Abs(T n) {
  return ((n) < 0 ? -(n) : (n));
}
template <class T>
inline T Max(T x, T y) {
  return (((y - x) >> (32 - 1)) & (x ^ y)) ^ y;
}
template <class T>
inline T Min(T x, T y) {
  return (((y - x) >> (32 - 1)) & (x ^ y)) ^ x;
}
template <class T>
inline T Swap(T &a, T &b) {
  a = a ^ b;
  b = a ^ b;
  a = a ^ b;
}
template <class T>
inline T gcd(T a, T b) {
  return (b) == 0 ? (a) : gcd((b), ((a) % (b)));
}
template <class T>
inline T lcm(T a, T b) {
  return ((a) / gcd((a), (b)) * (b));
}
int IR[] = {0, -1, 0, 1, -1, -1, 1, 1};
int IC[] = {1, 0, -1, 0, 1, -1, -1, 1};
struct an {
  long long int a;
  long long int b;
  bool operator<(const an &t) const { return b < t.b; }
} c[500100];
int main() {
  long long int i, j, k, n;
  while (scanf("%I64d", &n) != EOF) {
    for (i = 0; i < n; i++) {
      scanf("%I64d %I64d", &c[i].a, &c[i].b);
    }
    sort(c, c + n);
    j = 1;
    k = c[0].b;
    for (i = 0; i < n; i++) {
      if (c[i].a > k) {
        j++;
        k = c[i].b;
      }
    }
    printf("%I64d\n", j);
  }
  return 0;
}
