mu 1 2 3 mu 3 2 4 mu 3 4 5 mu 3 5 6 mu 2 6 7 mu 3 6 8 mu 2 8 9 mu 4 7 10 mu 6 7 11 mu 6 8 12 mu 11 5 13 mu 6 10 14 mu 7 10 15 mu 4 12 16 mu 10 11 17 mu 1 13 18 mu 1 17 19 oup 16 17 13 12 3 9 14 7 18 4 19 15 8 11 10 6 16 echo "Classes 8A 10AB 10CD 13AB 15AB 15CD 21AB 6C 6D 8E 12D 12E 14A 16A 24A 24B"