<span style="font-size: 24px; ">#include<stdio.h>
#include<iostream>
#include<algorithm>
#define M 1000
using namespace std;
struct node
{
	int x,y;
}p[M];

bool cmp(node a,node b)
{
	return (a.y<b.y);
}

int main ()
{
	int t;
	int i,k,l;
	while(~scanf("%d",&t)&&t)
	{
		for(i=0;i<t;i++)
			scanf("%d%d",&p[i].x,&p[i].y);
		sort(p,p+t,cmp);
		
		k=p[0].y;
		l=1;
		
		for(i=1;i<t;i++)
		{
			if(p[i].x>=k)
			{
				k=p[i].y;
				l++;
			}
		}
		printf("%d\n",l);
	}
	return 0;
}</span>