_  _   _  cout endl
 _         S clear
| _  _     num pop
| _ _      N cout
| ___  __  /
| ___      +
| _  __    N swap
|    _ _   10
|       _  1
| _        num lit
 _ __      N = len(S)
 _   _  _  str copy
| _   _    num push
| _  _     num pop
| ___   _  -
| _  __    N swap
|____  _   N = C
|__  _     S pop
|__  _  _  C copy
| _   _    num push
|____  _   N = C
 _    _    str push
 _ __      N = len(S)
 __  _     S pop
 __  _  _  C copy
 _ _       S in