A strongness of an even number is the number of times we can successively divide by 2 until we reach an odd number starting with an even number n.

For example, if n = 12, then
* 12 / 2 = 6
* 6 / 2 = 3

So we divided successively 2 times and we reached 3, so the strongness of 12 is `2`.

If n = 16 then
* 16 / 2 = 8
* 8 / 2 = 4
* 4 / 2 = 2
* 2 / 2 = 1

we divided successively 4 times and we reached 1, so the strongness of 16 is `4`


# Task

Given a closed interval `[n, m]`, return the even number that is the strongest in the interval. If multiple solutions exist return the smallest strongest even number.

Note that programs must run within the allotted server time; a naive solution will probably time out.


# Constraints
```if-not:ruby
1 <= n < m <= INT_MAX
```
```if:ruby
1 <= n < m <= 2^64
```


# Examples
```
[1, 2]    -->   2  # 1 has strongness 0, 2 has strongness 1
[5, 10]   -->   8  # 5, 7, 9 have strongness 0; 6, 10 have strongness 1; 8 has strongness 3
[48, 56]  -->  48

```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 = '"""Strongest even number in an interval kata\n\nDefines strongest_even(n, m) which returns the strongest even number in the set\nof integers on the interval [n, m].\n\nConstraints:\n    1. 1 <= n < m < MAX_INT\n\nNote:\n    1. The evenness of zero is need not be defined given the constraints.\n    2. In Python 3, the int type is unbounded. In Python 2, MAX_INT is\n    determined by the platform.\n\nDefinition:\n    A number is said to be more strongly even than another number if the\n    multiplicity of 2 in its prime factorization is higher than in the prime\n    factorization of the other number.\n"""\nfrom math import log2\n\n\ndef strongest_even(n, m):\n    """Returns the strongest even number in the set of integers on interval\n       [n, m].\n    """\n\n    #It can be shown that the largest power of 2 on an interval [n, m] will\n    #necessarily be the strongest even number. Check first if the interval\n    #contains a power of 2, by comparing the log2 of the endpoints.\n    if int(log2(m)) > int(log2(n)):\n        return 2**int(log2(m))\n\n    #Modify the endpoints exclude any odd numbers. If the two endpoints are\n    #equal, the original interval contains only a single even number. Return it.\n    n += n % 2\n    m -= m % 2\n    if n == m:\n        return n\n\n    #All optimizations and edge cases are exhausted. Recurse with the\n    #modified endpoints halved, and multiply the result by 2.\n    return 2*strongest_even(n // 2, m // 2)\n'
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'strongest_even'
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: 5562