red.cpp: In function 'int main()': red.cpp:50: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result red.cpp:51: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result red.cpp:53: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result