Circle of fifths
It can be seen that three of the scales each have two possible names: B major (with 5 sharps) can also be thought of as C flat major (with seven flats), F sharp major (with 6 sharps) can also be thought of as G flat major (with 6 flats), and C sharp major (with 7 sharps) can also be thought of as D flat major (with 5 flats).