Consider a game, wherein the player has to guess a target word. All the player knows is the length of the target word.

To help them in their goal, the game will accept guesses, and return the number of letters that are in the correct position.

Write a method that, given the correct word and the player's guess, returns this number.

For example, here's a possible thought process for someone trying to guess the word "dog":

```cs
CountCorrectCharacters("dog", "car"); //0 (No letters are in the correct position)
CountCorrectCharacters("dog", "god"); //1 ("o")
CountCorrectCharacters("dog", "cog"); //2 ("o" and "g")
CountCorrectCharacters("dog", "cod"); //1 ("o")
CountCorrectCharacters("dog", "bog"); //2 ("o" and "g")
CountCorrectCharacters("dog", "dog"); //3 (Correct!)
```
```python
count_correct_characters("dog", "car"); #0 (No letters are in the correct position)
count_correct_characters("dog", "god"); #1 ("o")
count_correct_characters("dog", "cog"); #2 ("o" and "g")
count_correct_characters("dog", "cod"); #1 ("o")
count_correct_characters("dog", "bog"); #2 ("o" and "g")
count_correct_characters("dog", "dog"); #3 (Correct!)
```

The caller should ensure that the guessed word is always the same length as the correct word, but since it could cause problems if this were not the case, you need to check for this eventuality:

```cs
//Throw an InvalidOperationException if the two parameters are of different lengths.
```
```python
#Raise an exception if the two parameters are of different lengths.
```

You may assume, however, that the two parameters will always be in the same case.

```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 count_correct_characters(a, b):\n    assert(len(a) == len(b))\n    return sum(a[i] == b[i] for i in range(len(a)))'
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'count_correct_characters'
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: 5654