
    A delivery fleet manager needs to optimize vehicle allocation for high-priority routes during peak hours. Starting with an initial fleet size, vehicles are assigned in pairs to critical delivery zones based on real-time traffic conditions. For each assignment round, two vehicles are deployed together for safety and efficiency purposes, continuing until no suitable vehicle pairs remain available. Calculate the total number of deployment combinations possible by summing the remaining vehicles after each pair assignment, starting from the initial fleet size and subtracting pairs until no complete pairs can be formed. For example, with 7 vehicles, calculate 7 + 5 + 3 + 1, representing the progressive states of available vehicles after each pair deployment.
    

    
def sum_series(n):
    """
    A delivery fleet manager needs to optimize vehicle allocation for high-priority routes during peak hours. Starting with an initial fleet size, vehicles are assigned in pairs to critical delivery zones based on real-time traffic conditions. For each assignment round, two vehicles are deployed together for safety and efficiency purposes, continuing until no suitable vehicle pairs remain available. Calculate the total number of deployment combinations possible by summing the remaining vehicles after each pair assignment, starting from the initial fleet size and subtracting pairs until no complete pairs can be formed. For example, with 7 vehicles, calculate 7 + 5 + 3 + 1, representing the progressive states of available vehicles after each pair deployment.
    

    """
def sum_series(n):
    """
    A delivery fleet manager needs to optimize vehicle allocation for high-priority routes during peak hours. Starting with an initial fleet size, vehicles are assigned in pairs to critical delivery zones based on real-time traffic conditions. For each assignment round, two vehicles are deployed together for safety and efficiency purposes, continuing until no suitable vehicle pairs remain available. Calculate the total number of deployment combinations possible by summing the remaining vehicles after each pair assignment, starting from the initial fleet size and subtracting pairs until no complete pairs can be formed. For example, with 7 vehicles, calculate 7 + 5 + 3 + 1, representing the progressive states of available vehicles after each pair deployment.
    

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