
    Design a credit risk assessment function that evaluates loan applicants across multiple credit quality tiers. Starting from an initial credit score threshold, the system needs to calculate the cumulative risk score by summing the values at each tier, where each subsequent tier represents a 2-point decrease from the previous threshold. The assessment continues until reaching the minimum acceptable score (when the adjusted threshold becomes zero or negative). This tiered evaluation helps determine the overall creditworthiness by considering the applicant's position across all qualifying tiers, with the total score influencing the final loan decision. The function should be flexible enough to work with different initial credit score thresholds while maintaining consistent tier intervals.
    

    
def sum_series(n):
    """
    Design a credit risk assessment function that evaluates loan applicants across multiple credit quality tiers. Starting from an initial credit score threshold, the system needs to calculate the cumulative risk score by summing the values at each tier, where each subsequent tier represents a 2-point decrease from the previous threshold. The assessment continues until reaching the minimum acceptable score (when the adjusted threshold becomes zero or negative). This tiered evaluation helps determine the overall creditworthiness by considering the applicant's position across all qualifying tiers, with the total score influencing the final loan decision. The function should be flexible enough to work with different initial credit score thresholds while maintaining consistent tier intervals.
    

    """
def sum_series(n):
    """
    Design a credit risk assessment function that evaluates loan applicants across multiple credit quality tiers. Starting from an initial credit score threshold, the system needs to calculate the cumulative risk score by summing the values at each tier, where each subsequent tier represents a 2-point decrease from the previous threshold. The assessment continues until reaching the minimum acceptable score (when the adjusted threshold becomes zero or negative). This tiered evaluation helps determine the overall creditworthiness by considering the applicant's position across all qualifying tiers, with the total score influencing the final loan decision. The function should be flexible enough to work with different initial credit score thresholds while maintaining consistent tier intervals.
    

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