app 运行报错 解决:     选择菜单：File->Settings->Build,Execution,Deployment->Instant Run，将右侧的顶部复选框关闭即可。

Description Bessie has been hired to build a cheap internet network among Farmer John’s N (2 <= N <= 1,000) barns that are conveniently numbered 1…N. FJ has already done some surveying, and found M (