Compilare: user.cpp: In function ‘void sieve(int)’: user.cpp:32:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < prime.size () && 1LL * i * prime[j] <= N; ++j) { ~~^~~~~~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:46:30: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d %d",&N,&MOD); ^