class program
    {
    define halfturn()
        {
        iterate( 2 )
            turnleft();
        }
        
    define findbeeper()
        {
        while( notNextToABeeper )
            move();
        }
        
    define return()
        {
        while( frontIsClear )
            move();
        halfturn();
        }
        
    define pickline()
        {
        if( nextToABeeper && frontIsClear )
            {
            move();
            if( nextToABeeper )
                {
                halfturn();
                move();
                halfturn();
                while( frontIsClear )
                    {
                    pickbeeper();
                    move();
                    }
                pickbeeper();
                }
            else
                {
                halfturn();
                move();
                }
            }
        else if( frontIsBlocked )
            turnoff();
        }
        
    program()
        {
        if( notNextToABeeper )
            findbeeper();
        else
            while( nextToABeeper )
                {
                pickline();
                if( notFacingWest )
                    {
                    halfturn();
                    return();
                    }
                else
                    turnoff();
                }
        findbeeper();
        turnoff();
        }
    }