# Problem Statement
Write a function that takes two string parameters, an IP (v4) address and a subnet mask, and returns two strings: the network block, and the host identifier.

The function does not need to support CIDR notation.

# Description
A single IP address with subnet mask actually specifies several addresses: a network block, and a host identifier, and a broadcast address. These addresses can be calculated using a bitwise AND operation on each bit.

(The broadcast address is not used in this kata.)

## Example
A computer on a simple home network might have the following IP and subnet mask:
```
IP: 192.168.2.1
Subnet: 255.255.255.0
(CIDR Notation: 192.168.2.1 /24)
```
In this example, the network block is: **192.168.2.0**. And the host identifier is: **0.0.0.1**. 

## bitwise AND 
To calculate the network block and host identifier the bits in each octet are ANDed together. When the result of the AND operation is '1', the bit specifies a network address (instead of a host address).

To compare the first octet in our example above, convert both the numbers to binary and perform an AND operation on each bit:
```
11000000 (192 in binary)
11111111 (255 in binary)
--------------------------- (AND each bit)
11000000 (192 in binary)
```
So in the first octet, '**192**' is part of the network address. The host identifier is simply '**0**'.

For more information see the [Subnetwork](http://en.wikipedia.org/wiki/Subnetwork) article on Wikipedia.

```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 ipv4__parser(ip_addr, mask):\n    ip, sMask = ip_addr.split("."), mask.split(".")\n    nb        = [ str(int(a)&int(b))   for a,b in  zip(ip, sMask) ]\n    hi        = [ str(int(a) - int(b)) for a, b in zip(ip, nb) ]\n    return  \'.\'.join(nb), \'.\'.join(hi) '
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'ipv4__parser'
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: 7074