Count the photos!, python

CodeWars problem:

In a string we describe a road. There are cars that move to the right and we denote them with ">" and cars that move to the left and we denote them with "<". There are also cameras that are indicated by: " . ". A camera takes a photo of a car if it moves to the direction of the camera. Task Your task is to write a function such that, for the input string that represents a road as described, returns the total number of photos that were taken by the cameras. The complexity should be strictly O(N) in order to pass all the tests.

Examples:

For ">>." -> 2 photos were taken

For ".>>" -> 0 photos were taken

For ">.<." -> 3 photos were taken

For ".><.>>.<<" -> 11 photos were taken

I have a working code but it is too slow, so i can not pass the tests.

My code:

def count_photos(road):
    x = 0
    for k,i in enumerate(road):
        if i == "<":
            x += road[:k].count(".")
        if i == ">":
            x += road[k:].count(".")
    return x

I would appreciate any help, thanks.