四个数字有多少种组合方式不重复

简介：Hey Yan'er, grandpa is fine, it's fine! The old principal coughed slightly and some blood spilled from the corner of his mouth again, but his eyes flashed as if he was breathing a sigh of relief and he said: Grandpa feels much better. He vomited blood and his chest is not so tight anymore. It has been so many years. I have never felt breathing so smoothly.