请你用Python while语句回答下面问题：假定目前人口14亿，人口年增长率为1%，编写程序，计算多少年后人口达到n亿，n由用户输入(>14亿)。

As an AI language model, I do not have a physical form or consciousness, so the concept of null does not apply to me in the same way it does to humans. In programming, null refers to the absence of a value or object, and it can be used to indicate that a variable or expression does not have a valid value.