curent.cpp: In function 'void dfs(int)': curent.cpp:20: warning: comparison between signed and unsigned integer expressions curent.cpp: In function 'int main()': curent.cpp:55: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result curent.cpp:56: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result curent.cpp:58: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result curent.cpp:60: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result curent.cpp:63: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result curent.cpp:65: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result curent.cpp:71: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result curent.cpp:75: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result