s2 s2 s1 s1 S3 S3 s4 s4 s5 s5 s7 s7 s8 s8 s9 s9 s10 s10 s12 s12 s13 s13 s14 s14 s15 s15 s16 s16 s21 s21 s22 s22 s23 s23 s24 s24 s25 s25 s26 s26 s28 s28 s27 s27