def queue_time(customers: list[int], n: int) -> int:
    if not customers:
        return 0
    if n == 1:
        return sum(customers)
    customer_amount = len(customers)
    if customer_amount <= n:
        return max(customers)

    customers.reverse()
    tills = [0] * n
    output = 0
    while customers:
        for idx in range(n):
            if tills[idx] == 0 and customers:
                tills[idx] = customers.pop() - 1
            else:
                tills[idx] -= 1
        output += 1

    return output + max(tills)