#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>

using namespace std;

const int N = 100010;
int n;
struct Segment
{
    int l, r;
    bool operator < (const Segment& t) const 
    {
        return r < t.r;
    }
}seg[N];

int main()
{
    scanf("%d", &n);
    for(int i = 0; i < n; i ++) scanf("%d %d", &seg[i].l, &seg[i].r);

    sort(seg, seg + n); //排序，默认按结构体前面的数据排序

    int ans = 0, last = -2e9;
    for(int i = 0; i < n; i ++)
    {
        if(last < seg[i].l) //直接判断边界，前面的右端点小于后面的左端点，即ans加一
        {
            ans ++;
            last = seg[i].r;
        }
    }
    cout << ans << endl;
    return 0;
}