The sharp symbol is #, which means raising the pitch of the basic note by a semitone. The flat symbol is b, which means lowering the pitch of the basic note by a semitone. There is also X, which is called a double sharp sign, which means that the pitch of the basic note is raised a whole step. (For example, X1 and X6 are pronounced as dol and la respectively). The double flat sign bb means lowering the pitch of the basic note by a whole step (for example, bb3 and bb5 are pronounced as double flat mi and double flat sol respectively). There is also a restoration number (cannot be typed here), which means restoring the pitch of the basic note that has been raised or lowered (pronounced restore*, restore*). These symbols are marked in the upper left corner of the note.