import java.util.ArrayList;
 
public class iStack implements stackInterface
{
	private ArrayList <location> data;//stores object
	private int top;//top of stack
	private int size;//number of objects in stack
 
 
	public iStack()
	{
		data = new ArrayList();
		top = -1;
		size = 0;
	}
 
	public boolean isEmpty()//return true if stack is empty
	{
		return top == -1;
	}
 
	public void push(Object x)//puts an object into the stack
	{
		data.add(x);
		top++;
		size++;
	}
 
	public Object pop()//removes top object from stack
	{
		int temp = top;
		top--;
		size--;return data.remove(temp);
	}
 
	public Object peekTop()//returns top of stack but doesn't delete 
	{
		return data.get(top);
	}
 
	public int getSize()//returns number of objects in stack
	{
		return size;
	}
}

public class location
{
	private int row;
	private int col;
 
	public location()
	{
		row = 0;
		col = 0;
	}//location
 
	public location(int r, int c)
	{
		row = r;
		col = c;
	}
 
	public int getRow()
	{ 
		return row;
	}//getrow
	public int getCol()
	{ 
		return col; 
	}//getcol
 
 
	public String toString()
	{	
		return("(row, col) = ("+ row + ", " + col + ").");
	}//toString
 
	public int compareTo(Object obj)
	{
		location loc =(location)obj;
		if (this.row != loc.getRow() || 
			this.col != loc.getCol())
			return -1;
		else
			return 0;
	}//compareTo
}//location

	int maze[][] = {{0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,1,0,0,0},
					{0,0,0,0,0,1,0,1,1,1,1,1,1,1,1,0,1,0,0,0},
					{0,1,0,0,0,1,0,0,0,0,0,0,0,1,0,0,1,0,1,1},
					{0,1,0,0,0,1,0,1,1,1,1,0,0,1,0,0,1,0,0,0},
					{0,1,0,0,0,1,0,1,1,1,1,0,0,1,0,0,1,0,0,0},
					{0,1,0,0,0,1,0,0,1,0,1,0,0,1,0,0,0,0,0,0},
					{0,0,0,0,0,0,0,0,1,0,1,0,0,1,0,0,0,0,0,0},
					{1,1,1,1,1,0,0,0,1,0,1,0,0,1,0,0,1,1,1,1},
					{0,0,0,0,0,0,0,0,0,0,1,0,0,1,0,0,1,1,1,1},
					{0,1,1,1,1,1,1,0,0,0,1,0,0,1,0,0,0,0,0,0}};