If the answer is YES, the second line should contain a possible numbering of flights.

如果答案是'YES '，那么第二行应该输出一个可行的航线编号方案。

youdao

If the answer is YES, the second line should contain a possible numbering of flights.

如果答案是'YES '，那么第二行应该输出一个可行的航线编号方案。

youdao