#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cstring>
#define x first
#define y second
using namespace std;
typedef pair<int,int> PII;
const int N = 100010;
int n;
PII s[N];
int main()
{
cin>>n;
//y是起点,x是终点
for(int i = 0; i<n; i++) cin>>s[i].y>>s[i].x;
sort(s,s+n);//按照终点x从小到大排序
int res = 0, ed = -2e9;
for(int i = 0; i<n; i++)
{
if(ed<s[i].y)
{
res++;
ed = s[i].x;
}
}
cout<<res<<endl;
return 0;
}