# is a sharp, b is a flat, #2 means that the 2 tone is raised by one semitone, and the pitch is equivalent to the 3 flat. In the simplified musical notation 12345671, 3 to 4 are semitones, and 7 to 1 are semitones. The difference between the other tones is two semitones, and there are five extra tones #1#2#4#5#6 in the middle.