锘??xml version="1.0" encoding="utf-8" standalone="yes"?>久久嫩草精品久久久精品一,国产精品免费网站在线观看,国产自产2019最新不卡http://www.shnenglu.com/Ylemzy/articles/103103.html鐏⒊榛?/dc:creator>鐏⒊榛?/author>Sun, 13 Dec 2009 06:31:00 GMThttp://www.shnenglu.com/Ylemzy/articles/103103.htmlThe Suspects
Description
Severe
acute respiratory syndrome (SARS), an atypical pneumonia of unknown
aetiology, was recognized as a global threat in mid-March 2003. To
minimize transmission to others, the best strategy is to separate the
suspects from others.
In the Not-Spreading-Your-Sickness University (NSYSU), there are
many student groups. Students in the same group intercommunicate with
each other frequently, and a student may join several groups. To
prevent the possible transmissions of SARS, the NSYSU collects the
member lists of all student groups, and makes the following rule in
their standard operation procedure (SOP).
Once a member in a group is a suspect, all members in the group are suspects.
However, they find that it is not easy to identify all the suspects
when a student is recognized as a suspect. Your job is to write a
program which finds all the suspects.
Input
The
input file contains several cases. Each test case begins with two
integers n and m in a line, where n is the number of students, and m is
the number of groups. You may assume that 0 < n <= 30000 and 0
<= m <= 500. Every student is numbered by a unique integer
between 0 and n鈭?, and initially student 0 is recognized as a suspect
in all the cases. This line is followed by m member lists of the
groups, one line per group. Each line begins with an integer k by
itself representing the number of members in the group. Following the
number of members, there are k integers representing the students in
this group. All the integers in a line are separated by at least one
space.
A case with n = 0 and m = 0 indicates the end of the input, and need not be processed.
Output
For each case, output the number of suspects in one line.