Compilare: main.cpp:5:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas] #pragma GCC optimization ("O3") main.cpp:6:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas] #pragma GCC optimization ("unroll-loops") main.cpp: In function 'int main()': main.cpp:61:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("farey.in", "r", stdin); ^ main.cpp:62:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("farey.out", "w", stdout); ^ main.cpp:64:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &k); ^