Many years ago, Roman numbers were defined by only `4` digits: `I, V, X, L`, which represented `1, 5, 10, 50`. These were the only digits used. The value of a sequence was simply the sum of digits in it. For instance:
```
IV = VI = 6
IX = XI = 11
XXL = LXX = XLX = 70
```
It is easy to see that this system is ambiguous, and some numbers could be written in many different ways. Your goal is to determine how many distinct integers could be represented by exactly `n` Roman digits grouped together. For instance:
```Perl
solve(1) = 4, because groups of 1 are [I, V, X, L]. 
solve(2) = 10, because the groups of 2 are [II, VI, VV, XI, XV, XX, IL, VL, XL, LL] corresponding to [2,6,10,11,15,20,51,55,60,100]. 
solve(3) = 20, because groups of 3 start with [III, IIV, IVV, ...etc]
```

`n <= 10E7`

More examples in test cases. Good luck!

```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 functools import lru_cache\n\nDIGITS = [1, 5, 10, 50]\nTHRESHOLD = 12\n\ndef solve_naive (n):\n    minimal = n * min(DIGITS)\n    maximal = n * max(DIGITS)\n    return maximal - minimal\n\n@lru_cache(maxsize=THRESHOLD)\ndef solve_brute (n):\n    from itertools import product\n    combinations = product(DIGITS, repeat=n)\n    values = list(map(sum, combinations))\n    return len(set(values))\n\n@lru_cache(maxsize=THRESHOLD)\ndef determine_delta (tries):\n    deltas = (solve_naive(n) - solve_brute(n)\n              for n in range(1, tries+1))\n    return max(deltas)\n\ndef solve (n):\n    if n > THRESHOLD:\n        return solve_naive(n) - determine_delta(THRESHOLD)\n    return solve_brute(n)\n'
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'solve'
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: 6176