The number of tripeptides formed by three different Aminoacids

The number of tripeptides formed by three different amino acids is six∙ Let  Ala Gly and Phe be the three α amino acids. They will form the following six tripeptides(i)Ala−Gly−Phe (ii)Gly−Ala−Phe (iii)Phe−Ala−Gly(iv)Ala−Phe−Gly(v)Gly−Phe−Ala(vi)Phe−Gly−Ala