1.


/**
 * FWP, Ausgewählte Probleme aus dem ACM Programming Contest, WS10/11
 * Problem: 11659 - Informants
 * Link: http://uva.onlinejudge.org/external/116/11659.pdf
 *
 * @author Philippe Brousse
 * @version 1.0, 10/27/2010
 *
 * Method : Ad-Hoc
 * Status : Accepted
 * Runtime: 0.444
 */
package informants;

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

/**
 *
 * @author Philippe Brousse
 */
public class Main
{

    /**
     * @param Kommandozeilenargumente
     */
    public static void main(String[] args)
    {
        Scanner input = new Scanner(System.in);
        int informants;
        int statements;
        while (true)
        {
            informants = input.nextInt();
            statements = input.nextInt();
            //Ende erreicht bei Eingabe 0 0
            if (informants == 0 && statements == 0)
            {
                input.close();
                return;
            }
            //Wer sagt was?
            boolean[] reliable = new boolean[informants];
            for (int i = 0; i < informants; i++)
            {
                reliable[i] = true;
            }

            for (int i = 0; i < statements; i++)
            {
                int inf = input.nextInt();
                int stat = input.nextInt();
                if (stat < 0)
                {
                    reliable[-stat - 1] = false;
                }
            }
            int rel = 0;
            for (boolean b : reliable)
            {
                if (b)
                {
                    rel++;
                }
            }

            System.out.println(rel);

        }
    }
}



2. 

/**
 * FWP, Ausgewählte Probleme aus dem ACM Programming Contest, SS10 
 * Problem: 11659 - Informants
 * Link: http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=78&page=show_problem&problem=2706
 * 
 * @author Evgeni Pavlidis 
 * @version 1.0, 06/02/2010
 * 
 * Method : Ad hoc
 * Status : Accepted
 * Runtime: 0.352
 */

import java.io.*;
import java.util.*;

class Main {

    public static void main(String...args)
    {
        Scanner sc = new Scanner(System.in);
        int i,a, x,y;
        while(true)
        {
            i = sc.nextInt();
            a = sc.nextInt();
            if( a == 0 && i == 0)
                break;

            boolean[] reliable = new boolean[i+1];
            for(int p = 1; p <= i; p++)
                reliable[p] = true;


            for(int ans = 0; ans < a; ans++)
            {
                x = sc.nextInt();
                y = sc.nextInt();

                if( y < 0)
                    reliable[-y] = false;
            }

            int c = 0;
            for(int p = 1; p <= i; p++)
                if(reliable[p])
                    c++;

            System.out.println(c);
        }
    }
}


2.

/**
 * FWP, Ausgewählte Probleme aus dem ACM Programming Contest, SS10 
 * Problem: 11659 - Informants
 * Link: http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=78&page=show_problem&problem=2706
 * 
 * @author Siegfried Ippisch 
 * @version 1.0, 09/06/2010
 * 
 * Method : Ad hoc
 * Status : Accepted
 * Runtime: 0.396
 */

import java.util.Scanner;

public class Main {
	
	public static void main(String[] args){
		Scanner input = new Scanner(System.in);
		
		while(true){
			
			int count = input.nextInt();
			int answers = input.nextInt();
			
			// informants Array, on start all are reliable
			boolean[] informants = new boolean[count+1];
			for(int i=1; i<=count; i++)
				informants[i] = true;
			
			// number of answers
			if(answers == 0 && count == 0)
				break;
			
			// if informant reliable -> change state of other informant
			for(int i=0; i<answers; i++){
				int x = input.nextInt();
				int y = input.nextInt();
				if(y<0)
					informants[-y] = false;
			}
			
			// count all reliable informants
			int c = 0;
			for(int i=1; i<=count; i++)
				if(informants[i])
					c++;
			
			System.out.println(c);
		}
		input.close();
	}
	
}