Heavenly stems (also known as ten stems) can be combined with earthly branches (also known as twelve branches) to form sixty flowers, which are used for dating years, months, days and hours. However, the odd-numbered heavenly stems (A, C, E, G, N) can only be combined with the odd-numbered earthly branches (Zi, Yin, Chen, Wu, Shen and Xu), and the even-numbered heavenly stems (B, D, Ji, Xin and Gui) can only be combined with the even-numbered earthly branches (Ugly, Hairy and Four). Therefore, there is only "self-ugliness, self-jealousy, self-ignorance, self-righteousness, self-hatred", and there will be no "self-discipline, self-yin, self-criticism, self-help, self-pity".