foo.cc: In function 'int main()':
foo.cc:6:9: error: 'system' was not declared in this scope
    6 |         system("ping www.luogu.com.cn > nul");
      |         ^~~~~~
foo.cc:9:13: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
    9 |   gets(sb[i]);
      |             ^
In file included from /usr/include/stdio.h:867,
                 from /usr/include/c++/9/cstdio:42,
                 from foo.cc:1:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:235:1: note: declared here
  235 | gets (char *__str)
      | ^~~~
foo.cc:9:13: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
    9 |   gets(sb[i]);
      |             ^
In file included from /usr/include/stdio.h:867,
                 from /usr/include/c++/9/cstdio:42,
                 from foo.cc:1:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:235:1: note: declared here
  235 | gets (char *__str)
      | ^~~~
foo.cc:7:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    7 |  scanf("%d%d%d\n",&n,&m,&s);
      |  ~~~~~^~~~~~~~~~~~~~~~~~~~~
foo.cc:9:7: warning: ignoring return value of 'char* gets(char*)', declared with attribute warn_unused_result [-Wunused-result]
    9 |   gets(sb[i]);
      |   ~~~~^~~~~~~
foo.cc:15:33: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   15 |  for(int i = 1;i <= m;i++) scanf("%s",list[i]);
      |                            ~~~~~^~~~~~~~~~~~~~

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