Consider the prime number `23`. If we sum the square of its digits we get:
`2^2 + 3^2 = 13`, then for `13: 1^2 + 3^2 = 10`, and finally for `10: 1^2 + 0^2 = 1`. 

Similarly, if we start with prime number `7`, the sequence is: `7->49->97->130->10->1`.

Given a range, how many primes within that range will eventually end up being `1`? 

The upperbound for the range is `50,000`. A range of `(2,25)` means that: `2 <= n < 25`. 

Good luck!

If you like this Kata, please try:

[Prime reversion](https://www.codewars.com/kata/59b46276afcda204ed000094)

[Domainant primes](https://www.codewars.com/kata/59ce11ea9f0cbc8a390000ed)

```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 = 'N = 10 ** 5\n\ndef sum_square_digits(n):\n    return sum((ord(d) - 48) ** 2 for d in str(n))\n\ndef reductible(n):\n    suite = set()\n    while n not in suite:\n        suite.add(n)\n        n = sum_square_digits(n)\n    return n == 1\n\nmax_digit_sum = 81 * len(str(N))\nsum_reduc = set(filter(reductible, range(max_digit_sum + 1)))\n\ndef primes(n):\n    sieve = n // 2 * [True]\n    for i in range(3, int(n**.5) + 1, 2):\n        if sieve[i // 2]:\n            sieve[i*i // 2::i] = [False] * ((n - i*i - 1) // (2*i) + 1)\n    return [2] + [2*i + 1 for i in range(1, n // 2) if sieve[i]]\n\nprime_reduc = [n for n in primes(N) if sum_square_digits(n) in sum_reduc]\n\nfrom bisect import bisect_left\ndef solve(a, b):\n    return bisect_left(prime_reduc, b) - bisect_left(prime_reduc, a)'
_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: 5348