avenues = 19
streets = 22
robot = (2, 6, 'E', 14)
walls = [
    (5, 6), 
    (7, 6), 
    (11, 6), 
    (15, 16), 
    (13, 16), 
    (9, 16), 
    (5, 16), 
    (4, 15), 
    (4, 13), 
    (4, 9), 
    (4, 7), 
    (12, 17), 
    (10, 17), 
    (13, 18), 
    (9, 18), 
    (15, 18), 
    (16, 19), 
    (8, 21), 
    (15, 22), 
    (17, 16), 
    (13, 4), 
    (15, 4), 
    (18, 5), 
    (18, 7), 
    (18, 9), 
    (18, 13), 
    (19, 12), 
    (20, 11), 
    (19, 10)
]
beepers = {}