=== 풀이 ===
{{{
//
//  main.cpp
//  usa_selfish
//
//  Created by 김 태진 on 12. 8. 14..
//  Copyright (c) 2012년 __MyCompanyName__. All rights reserved.
//

#include <stdio.h>
#include <stdlib.h>
#include <algorithm>
using namespace std;


typedef struct cow cow;
struct cow{
	int left;
	int right;
};

int compare(const void* a,const void* b);
int comp(cow a,cow b);

int main()
{
	int N,i,j,k;
	cow arr[50000],temp;
	cow array[10000];
	scanf("%d",&N);
	for(i=0;i<N;i++){
		scanf("%d %d",&arr[i].left,&arr[i].right);
		//	scanf("%d",&arr[i]);
	}
//	qsort((void*)arr, N, sizeof(int), comp);
	sort(arr,arr+N-1,comp);
	/*
	for(i=0;i<N-1;i++){
		for(j=i+1;j<N;j++){
			if(arr[i].right>arr[j].right){
				temp=arr[i];
				arr[i]=arr[j];
				arr[j]=temp;
			}
		}
	}*/
	array[0]=arr[0];
	k=1;
	for(i=0;i<N;i++){
		if(array[k-1].right<=arr[i].left){
			array[k]=arr[i];
			k++;
		}
	}
	
	printf("%d",k);
	
    return 0;
}


int compare(const void* a,const void* b)
{
	//((cow *)a)->right;
	return *(int*)a-*(int*)b;//*((cow *)a)->right - *((cow *)b)->right;
}
int comp(cow a,cow b)
{
	//if(a.left == b.left)return a.right<b.right;
    return a.right<b.right;
	/*
	if(a.right > b.right){
		return a.right > b.right;
	}else{
		return a.right < b.right;
	}
	 */
}


}}}
----
[ACM_ICPC/2012스터디]