# Task
 Dudka has `n` details. He must keep exactly 3 of them.

 To do this, he performs the following operations until he has only 3 details left:
```
He numbers them.
He keeps those with either odd or even numbers and throws the others away.```

 Dudka wants to know how many ways there are to get exactly 3 details. Your task is  to help him calculate it.

# Example

 For `n = 6`, the output should be `2`.
 ```
Dudka has 6 details, numbered 1 2 3 4 5 6. 
He can keep either details with numbers 1, 3, 5, 
or with numbers 2, 4, 6. 
Both options leave him with 3 details, 
so the answer is 2.```

 For `n = 7`, the output should be `1`.
 ```
Dudka has 7 details, numbered 1 2 3 4 5 6 7. 
He can keep either details 1 3 5 7, or details 2 4 6. 
If he keeps details 1 3 5 7 , 
he won't be able to get 3 details in the future, 
because at the next step he will number them 1 2 3 4 
and will have to keep either details 1 3, or 2 4, 
only two details anyway. 
That's why he must keep details 2 4 6 at the first step, 
so the answer is 1.```

# Input/Output


 - `[input]` integer `n`

  `3 ≤ n ≤ 10^9`


 - `[output]` an integer

  The number of ways to get exactly 3 details.

```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\n\n@lru_cache()\ndef three_details(n, count=0):\n    even, odd = n//2, n//2 + n%2\n    if n == 3:\n        return 1\n    elif n < 3:\n        return 0\n    return three_details(n-even) + three_details(n-odd)'
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'three_details'
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: 5616