# Introduction

The Condi (Consecutive Digraphs) cipher was introduced by G4EGG (Wilfred Higginson) in 2011. The cipher preserves word divisions, and is simple to describe and encode, but it's surprisingly difficult to crack. 

# Encoding Algorithm

The encoding steps are:
- Start with an `initial key`, e.g. `cryptogram`
- Form a `key`, remove the key duplicated letters except for the first occurrence
- Append to it, in alphabetical order all letters which do not occur in the `key`.  
  The example produces: `cryptogambdefhijklnqsuvwxz`
- Number the `key alphabet` starting with 1.
```python
1  2  3  4  5  6  7  8  9  10 11 12 13
c  r  y  p  t  o  g  a  m  b  d  e  f 
14 15 16 17 18 19 20 21 22 23 24 25 26
h  i  j  k  l  n  q  s  u  v  w  x  z
```
- One of the inputs to encoding algorithm is an `initial shift`, say `10`
- Encode the first letter of your `message` by moving 10 places to the right from the letter's position in the key alphabet. If the first letter were say `o` then the letter 10 places to the right in the `key alphabet` is `j`, so `o` would be encoded as `j`. If you move past the end of the key alphabet you wrap back to the beginning. For example if the first letter were `s` then counting 10 places would bring you around to `t`.
- Use the position of the previous plaintext letter as the number of places to move to encode the next plaintext number. If you have just encoded an `o` (position 6) , and you now want to encode say `n`, then you move 6 places to the right from `n` which brings you to `x`.
- Keep repeating the previous step until all letters are encoded.

Decoding is the reverse of encoding - you move to the left instead of to the right.

# Task

Create two functions - `encode`/`Encode` and `decode`/`Decode` which implement Condi cipher encoding and decoding.

# Inputs

- `message` - a string to encode/decode
- `key` - a key consists of only lower case letters
- `initShift` - a non-negative integer representing the initial shift

# Notes
- Don't forget to remove the duplicated letters from the `key` except for the first occurrence 
- Characters which do not exist in the `key alphabet` should be coppied to the output string exactly like they appear in the `message` string
- Check the test cases for samples

```python

USER_FILENAME = "<user_code>"
import sys, json, builtins
import math, heapq, bisect, itertools, functools, collections, statistics, fractions, decimal, operator, array, random, re, string, os, pathlib
try:
    import resource as _res
except Exception:
    _res = None
from collections import Counter, defaultdict, deque, OrderedDict
from functools import lru_cache, reduce
from itertools import accumulate, permutations, combinations, product
from math import gcd, ceil, floor, sqrt
from decimal import Decimal
try:
    from typing import *
except Exception:
    pass
try:
    sys.setrecursionlimit(1_000_000)
except Exception:
    pass
try:
    import site as _site
    try:
        _sys_sites = _site.getsitepackages() if hasattr(_site, "getsitepackages") else []
        for _p in _sys_sites:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
    try:
        _usp = _site.getusersitepackages()
        if isinstance(_usp, str):
            _usp = [_usp]
        for _p in _usp:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
except Exception:
    pass

def _disabled_input(*args, **kwargs):
    raise RuntimeError("input() is disabled in callable mode")
builtins.input = _disabled_input

ns = {"__name__": "__judge__"}  # prevent if __name__ == "__main__" blocks
for _k, _v in list(globals().items()):
    if not _k.startswith("_"):
        ns[_k] = _v
_CODE = "def encode(message, key, shift): return cipher(message, key, shift, 1)\n\ndef decode(message, key, shift): return cipher(message, key, -shift, 0)\n\ndef cipher(message, key, shift, mode):\n    key = tuple(dict.fromkeys(key.lower() + 'abcdefghijklmnopqrstuvwxyz'))\n    res = ''\n    for char in message:\n        if char in key:\n            i = key.index(char)\n            char = key[(i + shift) % 26]\n            shift = i + 1 if mode else -key.index(char) - 1\n        res += char\n    return res"
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'encode'
if _fn_name:
    if "Solution" in ns:
        try:
            _obj = ns["Solution"]()
            if hasattr(_obj, _fn_name):
                _target = getattr(_obj, _fn_name)
        except Exception:
            _target = None
    if _target is None and _fn_name in ns and callable(ns[_fn_name]):
        _target = ns[_fn_name]
# Fallback: if there's exactly one user-defined function, use it
if _target is None:
    _cands = [v for k, v in ns.items() if callable(v) and getattr(v, "__module__", "") in ("__judge__", "__main__")]
    _user_funcs = [c for c in _cands if getattr(c, "__name__", "").startswith("_") is False]
    if len(_user_funcs) == 1:
        _target = _user_funcs[0]
if _target is None:
    raise RuntimeError(f"Could not resolve callable '{_fn_name}'")

_raw = sys.stdin.read().strip()
if _raw:
    _parsed = json.loads(_raw)
    if isinstance(_parsed, dict):
        _kwargs = _parsed.get("kwargs", {})
        _args = _parsed.get("args", [])
    else:
        _args, _kwargs = _parsed, {}
else:
    _args, _kwargs = [], {}
if not isinstance(_args, (list, tuple)):
    _args = [_args]
_res = _target(*_args, **_kwargs)
try:
    sys.stdout.write(repr(_res) + "\n")
except Exception:
    pass

```

Measured memory_bytes: 6827