C :

#include <stdio.h>
#include <stdlib.h>
#define FOR(i,n) for(i=0;i<n;i++)

struct node{
    int begin,end,pos;
};

int cmp(const void *a, const void *b){
    struct node e1 = *(struct node *)a;
    struct node e2 = *(struct node *)b;
    return e1.end - e2.end;
}

int main(){
    int n;
    int i,j,max;
    struct node f[105];

    while(~scanf("%d", &n), n){
        FOR(i,n){
            scanf("%d%d", &f[i].begin, &f[i].end);
        }
        qsort(f, n, sizeof(f[0]),cmp);
        FOR(i,n){
            f[i].pos = 0;
            FOR(j,i){
                if(f[j].end<=f[i].begin&&f[j].pos>f[i].pos)
                    f[i].pos = f[j].pos;
            }
            f[i].pos++;
        }

        /*
        FOR(i,n)
            printf("i=%d begin=%d end=%d pos=%d\n", i+1, f[i].begin,f[i].end,f[i].pos);
        */
        max = -1;
        FOR(i,n){
            if(max<f[i].pos)
                max = f[i].pos;
        }
        printf("%d\n", max);

    }
    return 0;
}

C++ :

#include<cstdio>
#include<algorithm>
using namespace std;

struct tv
{
	int s;
	int e;
}a[100],t;

bool cmp(tv a,tv b)
{
	if(a.e==b.e)
		return a.s<b.s;
	else
		return a.e<b.e;
}

int main()
{
	int n,i,k;
	while(scanf("%d",&n)!=EOF,n)
	{
		k=1;
		for(i=0;i<n;i++)
			scanf("%d%d",&a[i].s,&a[i].e);
		sort(a,a+n,cmp);
		t.s=a[0].s;
		t.e=a[0].e;
		for(i=1;i<n;i++)
		{
			if(a[i].e>t.e)
			{
				if(a[i].s>=t.e)
				{
					k++;
					t.s=a[i].s;
					t.e=a[i].e;
				}
			}
		}
		printf("%d\n",k);
	}
	return 0;
}

Java :

import java.util.*;


public class Main{
	public static void main(String[] args){
		Scanner scan = new Scanner(System.in);
		
		while(scan.hasNextInt()){
			int n = scan.nextInt();
			if(n == 0){
				break;
			}
			
			Tv[] tvs = new Tv[n];
			int i,j,k;
			
			for(i=0; i<n; i++){
				tvs[i] = new Tv(scan.nextInt(), scan.nextInt());				
			}
			
			for(i=0; i<n; i++){
				k = i;
				
				for(j=i+1; j<n; j++){
					if(tvs[j].s < tvs[k].s){
						k = j;
					}
				}
				
				Tv tv = tvs[i];
				tvs[i] = tvs[k];
				tvs[k] = tv;
			}
			
			int[] dp = new int[n];
			int max = dp[0] = 1;
			
			for(i=1; i<n; i++){
				k = 0;
				
				for(j=0; j<i; j++){
					if(tvs[j].e<=tvs[i].s && dp[j]>k){
						k = dp[j];
					}
				}
				
				dp[i] = k+1;
				
				if(dp[i] > max){
					max = dp[i];
				}
			}
			
			System.out.println(max);
		}
	}
}

class Tv{
	Tv(int s, int e){
		this.s = s;
		this.e = e;
	}
	
	int s;
	int e;
}