
    In a fleet management system, you need to calculate the total number of route combinations while systematically eliminating pairs of alternative paths. Starting with an initial number of available delivery routes, the system removes two alternative routes in each optimization step until no viable alternatives remain. For each step, calculate the remaining route options by subtracting twice the step number from the initial routes. Sum up all these remaining route options across all steps to determine the total number of route combinations considered during the optimization process. The process continues until the remaining route count becomes zero or negative, ensuring all possible route reduction scenarios are evaluated.
    

    
def sum_series(n):
    """
    In a fleet management system, you need to calculate the total number of route combinations while systematically eliminating pairs of alternative paths. Starting with an initial number of available delivery routes, the system removes two alternative routes in each optimization step until no viable alternatives remain. For each step, calculate the remaining route options by subtracting twice the step number from the initial routes. Sum up all these remaining route options across all steps to determine the total number of route combinations considered during the optimization process. The process continues until the remaining route count becomes zero or negative, ensuring all possible route reduction scenarios are evaluated.
    

    """
def sum_series(n):
    """
    In a fleet management system, you need to calculate the total number of route combinations while systematically eliminating pairs of alternative paths. Starting with an initial number of available delivery routes, the system removes two alternative routes in each optimization step until no viable alternatives remain. For each step, calculate the remaining route options by subtracting twice the step number from the initial routes. Sum up all these remaining route options across all steps to determine the total number of route combinations considered during the optimization process. The process continues until the remaining route count becomes zero or negative, ensuring all possible route reduction scenarios are evaluated.
    

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