Find the closest prime number under a certain integer ```n``` that has the maximum possible amount of even digits.

For ```n = 1000```, the highest prime under ```1000``` is ```887```, having two even digits (8 twice)

Naming ```f()```, the function that gives that prime, the above case and others will be like the following below.
```
f(1000) ---> 887 (even digits: 8, 8)

f(1210) ---> 1201 (even digits: 2, 0)

f(10000) ---> 8887

f(500) ---> 487

f(487) ---> 467
``` 
Features of the random tests:
```
Number of tests = 28
1000 <= n <= 5000000
```

Enjoy it!!

```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 = 'from bisect import bisect_left as bisect\n\nn = 5000000\nsieve, PED, PED_DATA = [0]*((n>>1)+1), [], []\nfor i in range(3, n+1, 2):\n    if not sieve[i>>1]:\n        for j in range(i**2>>1, (n+1)>>1, i): sieve[j] = 1\n        s = str(i)\n        nEveD = sum(s.count(d) for d in "02468")\n        if nEveD:\n            PED.append(i)\n            PED_DATA.append( (nEveD,len(s)-1) )\n\ndef f(n):\n    idx = bisect(PED, n)-1\n    m, (nEveD, l) = PED[idx], PED_DATA[idx]\n    \n    for c in range(idx):\n        mc, (nEveDc, lc) = PED[idx-c], PED_DATA[idx-c]\n        if nEveDc > nEveD:\n            m, nEveD = mc, nEveDc\n        if lc < nEveD: break\n    return m'
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'f'
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: 5550