import java.util.*;
import java.awt.Point;

class Pattern
{
  private int img[];
  private int width;
  private int height;
  private Vector <Point>edge;
  
  
  public Pattern(int img[],int width,int height)
    {
      this.img  = new int[width*height];
      this.width  = width ;
      this.height = height ;
      for(int i=0;i < width*height;i++)
        {
          this.img[i] = img[i];
        }
      
      
      edge = new Vector<Point>();
      
      }
  
  public int index(int x,int y)
    {
      if( 0 <= x && x<width&&
          0 <= y && x<height
          )
        {
          return img[width*y+x];
        }
      else
        {
          throw new ArithmeticException();
        }
    }
  
  public Point putEdge()
    {
      if(0 ==edge.size()){return null;}
      Point po;
      po = edge.get(0);
      edge.removeElementAt(0);
      return po;
    }
  
  
  public int searchEdge()
    {
      edge.removeAllElements();
      int sum=0;
      int edge_sum=0;

      for(int y= 1; y< height-1;y++)
        for(int x = 1;x <width-1;x++)
          {
                            
            if(index(x,y) >0)
              {try{
                sum = 0;
                
                if(index(x,y+1) > 0){sum++;}
                
                if(index(x+1,y+1) > 0){sum++;}
                if(index(x+1,y) > 0){sum++;}
                if(index(x+1,y-1) > 0){sum++;}
                
                if(index(x-1,y-1) > 0){sum++;}
                if(index(x-1,y) > 0){sum++;}
                if(index(x-1,y+1) > 0){sum++;}
                
                if(index(x,y-1) > 0){sum++;}

                if(sum == 1)
                  {
                    edge.add(new Point(x,y));
                    edge_sum++;
                  }
              }catch(Exception e){;}}
          }
      return edge_sum;
    } 
}