SP59 BIA - Bytelandian Information Agency

Bytelandian Information Agency (BIA) uses a net of _n_ computers. The computers are numbered from _1_ to _n_, and the computer number _1_ is a server. The computers are connected by one-way information channels. Every channel connects a pair of computers. The whole network is organised in such a way that one can send information from the server to any other computer either directly or indirectly. When BIA acquires new information, the information is put on the server and propagated in the net. The chief of BIA considers what would happen if one computer stopped working (was blown away by terrorists for example). It could happen that some other computers would stop receiving information from the server, because the broken computer was a necessary transmitter. We will call such computers _critical_. For example in the situation in the picture below the critical computers are _1_ and _2_. _1_ is the server and all information sent from the server to _3_ has to go through _2_.  ### Task Write a program which - reads a description of the net from standard input, - finds all critical computers. - writes the numbers of critical computers to standard output.

Ten test cases (given one under another, you have to process all!). Each test case consists of several lines. In the first line there are numbers _n_ and _m_. _n_ denotes the number of computers in the net,_(2

For every testcase your program should write two lines. In the first line _k_ - the number of critical computers in the net. In the second line _k_ numbers separated by single spaces - the numbers of critical computers in increasing order.