
    A transit authority needs to calculate the total number of bus stops serviced across different versions of a route as it progressively reduces service during off-peak hours. Starting with the full route of n stops, the authority removes 2 stops at a time until reaching minimum coverage, creating multiple versions of the route throughout the day. Each version services n stops, then (n-2) stops, then (n-4) stops, and so on until the number of remaining stops becomes zero or negative. Write a function that calculates the total number of bus stops serviced across all versions of the route combined, helping the authority track service coverage during the transition from peak to off-peak hours.
    

    
def sum_series(n):
    """
    A transit authority needs to calculate the total number of bus stops serviced across different versions of a route as it progressively reduces service during off-peak hours. Starting with the full route of n stops, the authority removes 2 stops at a time until reaching minimum coverage, creating multiple versions of the route throughout the day. Each version services n stops, then (n-2) stops, then (n-4) stops, and so on until the number of remaining stops becomes zero or negative. Write a function that calculates the total number of bus stops serviced across all versions of the route combined, helping the authority track service coverage during the transition from peak to off-peak hours.
    

    """
def sum_series(n):
    """
    A transit authority needs to calculate the total number of bus stops serviced across different versions of a route as it progressively reduces service during off-peak hours. Starting with the full route of n stops, the authority removes 2 stops at a time until reaching minimum coverage, creating multiple versions of the route throughout the day. Each version services n stops, then (n-2) stops, then (n-4) stops, and so on until the number of remaining stops becomes zero or negative. Write a function that calculates the total number of bus stops serviced across all versions of the route combined, helping the authority track service coverage during the transition from peak to off-peak hours.
    

    """
    if n < 1:
        return 0
    else:
        return n + sum_series(n - 2)