According to ISO 8601, the first calendar week (1) starts with the week containing the first thursday in january.
Every year contains of 52 (53 for leap years) calendar weeks.

**Your task is** to calculate the calendar week (1-53) from a given date.
For example, the calendar week for the date `2019-01-01` (string) should be 1 (int).

Good luck 👍

See also [ISO week date](https://en.wikipedia.org/wiki/ISO_week_date) and [Week Number](https://en.wikipedia.org/wiki/Week#Week_numbering) on Wikipedia for further information about calendar weeks.

On [whatweekisit.org](http://whatweekisit.org/) you may click through the calender and study calendar weeks in more depth.

*heads-up:* `require(xxx)` has been disabled


Thanks to @ZED.CWT, @Unnamed and @proxya for their feedback.

```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 isLeap(y):\n    return y % 400 == 0 or (y % 100 != 0 and y % 4 == 0)\n\ndef numDays(y, m, d):\n    return sum([31, 29 if isLeap(y) else 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31][:m - 1]) + d\n\ndef whatDay_Jan1st(y):  # monday: 1, tuesday: 2, ..., sunday: 7\n    y = (y - 1) % 400\n    return ((y // 100) * (76 * 1 + 24 * 2) + ((y % 100) // 4) * (1 + 1 + 1 + 2) + (y % 4)) % 7 + 1\n\ndef get_calendar_week(date_string):\n    y, m, d = map(int, date_string.split("-"))\n    if (m == 12 and d in [29, 30, 31]):\n        s = whatDay_Jan1st(y + 1)\n        if (s == 4 or (s == 3 and d in [30, 31]) or (s == 2 and d == 31)):\n            return 1\n    s = whatDay_Jan1st(y)\n    if (m == 1 and ((s == 5 and d in [1, 2, 3]) or (s == 6 and d in [1, 2]) or (s == 7 and d == 1))):\n        y, m, d = y - 1, 12, 28\n        s = whatDay_Jan1st(y)\n\n    dateW01_1 = [1, 0, -1, -2, 4, 3, 2][s - 1]\n    return (numDays(y, m, d) - dateW01_1) // 7 + 1'
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'get_calendar_week'
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: 6058