In the Western music tradition, pitches are named after the first seven letters of the alphabet, A, B, C, D, E, F, and G.
D [ре] E [ми] F [фа] и G [соль]. Далее цикл повторяется: A [ля] B [си] С [до] D [ре] E [ми] F [фа] G [соль] A [ля] B [си] С [до] D [ре] E [ми] F [фа] G [соль] и так далее.