Poj Solution 1716

http://poj.org/problem?id=1716

//* @author: 82638882@163.com
import java.io.*;
import java.util.*;
public class Main
{
 public static void main(String[] args) throws NumberFormatException, IOException
 {
    InputStreamReader is=new InputStreamReader(System.in);
    BufferedReader in=new BufferedReader(is);
    int a=Integer.parseInt(in.readLine());
    int ans=2,i;
    my[] arr=new my[a];
    String[] ss;
    for(i=0;i< a;i++)
    {
         ss=in.readLine().split(" ");
      int x=Integer.parseInt(ss[0]);
      int y=Integer.parseInt(ss[1]);
      arr[i]=new my(x,y);
     }
     Arrays.sort(arr);
     int x=arr[0].b,y=x-1;
     for(i=1;i< a;i++)
     {
      if(y>=arr[i].a){}
      else if(x>=arr[i].a)
      {
        y=x;
        x=arr[i].b;
        ans++;
       }
       else
       {
        x=arr[i].b;
        y=x-1;
        ans+=2;
        }
       }
    System.out.printf("%dn",ans);
  }
}
class my implements Comparable< my>
{
    public int a,b;
    public my(int x,int y)
    {
        a=x;
        b=y;
    }
    public int compareTo(my o) {
        return b-o.b;
    }
}