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 = "def strongest_even(n, m):\n    x, y = bin(n)[2:], bin(m)[2:]\n    if len(x) < len(y): return 1 << len(y)-1\n    i = next(i for i in range(len(x)) if x[i] != y[i])\n    res = x[:i] + ('1' if '1' in x[i:] else '0') + '0'*(len(x)-i-1)\n    return int(res, 2)"
_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: 5710