sub.cpp: In constructor 'InputReader::InputReader(const char*)': sub.cpp:20: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result sub.cpp: In constructor 'InputReader::InputReader(const char*)': sub.cpp:20: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result sub.cpp: In constructor 'InputReader::InputReader(const char*)': sub.cpp:20: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result sub.cpp: In member function 'void InputReader::advance()': sub.cpp:47: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result sub.cpp: In function 'int main()': sub.cpp:174: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result