四个数字有多少种组合方式不重复

简介：Although there is a map of eastern Liaoning and southern Liaoning, Ming also has a considerable understanding of the sea conditions in eastern Liaoning and southern Liaoning. However, Ming is not very clear whether the situation on the shore has changed or how many forts and walled cities the Jianlu built. And this is The purpose of these cartilage that surrendered to the Jianqi in the first place.