00101000000000100000000000000000   0. -20 to c
10101000000000010000000000000000   1. Sub. 21
10100000000001100000000000000000   2. c to 5
10100000000000100000000000000000   3. -5 to c
00000000000001110000000000000000   4. Stop
00000000000000000000000000000000   5. 0