Poj Solution 1548

http://poj.org/problem?id=1548

/* @author: */
import java.util.*;
public class Main {
 public static void main(String[] args){
  Scanner sc = new Scanner(System.in);
  int x[]=new int[1000], y[]=new int[1000];
  boolean sign[]=new boolean[1000];
  int a, b, n, m, i, ans;
  while( true )
  {
     n = 0;
     while( true )
     {
        x[n]=sc.nextInt();
        y[n]=sc.nextInt();
        if( x[n] < 0 && y[n] < 0 ) return ;
        if( x[n] == 0 && y[n] == 0 ) break;
        sign[n] = false;
        n++;
     }
                
     for( m=0, ans = 0; m< n; ans++ )
     {
        a = 0;
        b= 0;
        for( i=0; i< n; i++ )
          if( !sign[i] && x[i]>=a && y[i] >=b )
          {
            sign[i] = true;
            m++;
            a = x[i];
            b = y[i];
          }
   }
           
   System.out.printf( "%dn", ans );
  }
 }
}