I'm trying to display something but it keeps booting up and immediately quitting.

the console comes up with:

```py
 line 77, in main
    if event.type == MOUSEBUTTONDOWN:
NameError: name 'MOUSEBUTTONDOWN' is not defined
Traceback (most recent call last): line 89, in <module>
    main()

```

but I didn't think any of these problems would create this but I'm not sure.

```py
def main(): #main game loop
    clock = pygame.time.Clock()
    run = True
    while run:
        clock.tick(FPS)
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                run = False
        if event.type == MOUSEBUTTONDOWN:
            if event.button == 1:
                clicking = True

        draw_window(startbutton, exitbutton,)

    pygame.quit()

if __name__ == "__main__":
    main()

```