Compilare: main.cpp: In function 'void get_ll(ll&)': main.cpp:15:36: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(buf , sz , 1 , stdin); ^ main.cpp:29:36: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(buf , sz , 1 , stdin); ^ main.cpp: In function 'int main()': main.cpp:135:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("sec.in" , "r" , stdin); ^ main.cpp:136:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("sec.out" , "w" , stdout); ^