Compilare: main.cpp: In function 'll smart()': main.cpp:133:28: warning: unused variable 'delta' [-Wunused-variable] ll delta = ans; ^~~~~ main.cpp: In member function 'char InParser::read_ch()': main.cpp:22:50: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(buff, 1, 4096, fin); ^