# set A to 9, B to 1
1 inc A 2
2 inc A 3
3 inc A 4
4 inc A 5
5 inc A 6
6 inc A 7
7 inc A 8
8 inc A 9
9 inc A 10
10 inc B 11

# move B to C, double it while moving
11 dec B 12 14
12 inc C 13
13 inc C 11

# move C to B
14 dec C 15 16
15 inc B 14

# decrease A, halt when A can no longer be decreased
16 dec A 11 17
17 halt