HDU2037

#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;
struct Node
{
    int start;
    int stop;
}a[101];
bool cmp(const Node a,const Node b)
{
    if(a.stop!=b.stop)return a.stop<b.stop;
}
int main()
{
    int n;
    while(scanf("%d\n",&n),n!=0)
    {
        for(int i=0;i<n;i++)
            scanf("%d %d",&a[i].start,&a[i].stop);
        sort(a,a+n,cmp);
        int result = 1;
        int j=0;
        for(int i=0;i<n;i++)
        {
            if(a[i].start>=a[j].stop)
                {result++;j=i;}
        }
        printf("%d\n",result);
    }

}