#include <iostream>
#include <algorithm>
#include <queue>

#define x first
#define y second

using namespace std;

typedef pair<int, int> PII;

const int N = 1e5 + 10;

int n;
PII a[N];

int main()
{
    scanf("%d", &n);
    for(int i = 0; i < n; i++) scanf("%d%d", &a[i].x, &a[i].y);

    sort(a, a + n);

    priority_queue<int, vector<int>, greater<int> > heap; //维护所有已建组的右端点
    heap.push(a[0].y); //将第一个区间新建为第一个组
    for(int i = 1; i < n; i++)
    {
        if(a[i].x <= heap.top()) heap.push(a[i].y); //新建一个组
        else heap.pop(), heap.push(a[i].y); //加入堆顶的组
    }

    printf("%d", heap.size());

    return 0;
}