MPI_Recv(&recv_buff, 1, MPI_INT, MPI_ANY_SOURCE, MPI_ANY_TAG, MPI_COMM_WORLD, &status);
printf("Message received from %d\n", recv_buff);
MPI_Send(&recv_buff, 1, MPI_INT, status.MPI_SOURCE, 42, MPI_COMM_WORLD);
MPI_Recv(&recv_buff, 1, MPI_INT, MPI_ANY_SOURCE, MPI_ANY_TAG, MPI_COMM_WORLD, &status);
printf("Message received from %d\n", recv_buff);
MPI_Send(&recv_buff, 1, MPI_INT, status.MPI_SOURCE, 42, MPI_COMM_WORLD);