
    A delivery fleet manager needs to calculate the total number of viable delivery routes throughout a day as traffic congestion increases. Starting with an initial number of routes, the available options decrease by 2 for each subsequent time block due to growing traffic density. The calculation should sum up all available route options across time blocks, continuing until no viable routes remain. For example, if starting with 7 routes, the sum would be 7 + 5 + 3 + 1 = 16, representing the total route options across all time blocks. Write a function that performs this calculation for any given initial number of routes to help the fleet manager optimize delivery planning.
    

    
def sum_series(n):
    """
    A delivery fleet manager needs to calculate the total number of viable delivery routes throughout a day as traffic congestion increases. Starting with an initial number of routes, the available options decrease by 2 for each subsequent time block due to growing traffic density. The calculation should sum up all available route options across time blocks, continuing until no viable routes remain. For example, if starting with 7 routes, the sum would be 7 + 5 + 3 + 1 = 16, representing the total route options across all time blocks. Write a function that performs this calculation for any given initial number of routes to help the fleet manager optimize delivery planning.
    

    """
def sum_series(n):
    """
    A delivery fleet manager needs to calculate the total number of viable delivery routes throughout a day as traffic congestion increases. Starting with an initial number of routes, the available options decrease by 2 for each subsequent time block due to growing traffic density. The calculation should sum up all available route options across time blocks, continuing until no viable routes remain. For example, if starting with 7 routes, the sum would be 7 + 5 + 3 + 1 = 16, representing the total route options across all time blocks. Write a function that performs this calculation for any given initial number of routes to help the fleet manager optimize delivery planning.
    

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