Table for While loop

import java.util.*;
public class p180ex6
{

    static Scanner in= new Scanner(System.in);
    public static void main(String[] args)
    {
        int counter = 0;
        int a = 0;
            while(a >= 0)
            {
                a = in.nextInt();
                if(a>0)
                counter ++;
            }
        System.out.println(counter);
    }

}