mu 1 2 3 mu 3 2 4 mu 3 4 5 mu 3 5 6 mu 6 5 7 mu 7 4 8 mu 3 7 9 mu 9 6 10 mu 2 6 11 mu 11 7 12 mu 5 6 13 mu 13 8 14 mu 3 12 15 mu 6 7 16 iv 16 17 mu 4 8 18 mu 18 14 19 oup 11 19 5 12 8 10 14 15 6 17 3 7 echo "Classes 9A 14ABC 19ABC 26ABC 37ABC 6C 9D 18A 18B 21A 27B"