# In this program the robot picks up
# all the trash lying around in the
# 10 by 10 grid.
# There can be more than one piece of
# trash in the same spot.

def turn_right():
    repeat(turn_left,3)
    
def pick_up_all_and_move():
    while on_beeper():
        pick_beeper()
    move()

# deals with one row
def one_row():
    repeat(pick_up_all_and_move, 9)

# deals with one row from left to right,
# turns around and goes up one line,
# deals with the next row,
# turns around and goes up one line
def two_rows():
    one_row()
    turn_around_left()
    one_row()
    turn_around_right()

def turn_around_left():
    turn_left()
    if front_is_clear():
        pick_up_all_and_move()
        turn_left()

def turn_around_right():
    turn_right()
    if front_is_clear():
        pick_up_all_and_move()
        turn_right()

repeat(two_rows, 5)
turn_off()