#### Background: 
 

A linear regression line has an equation in the form `$Y = a + bX$`, where `$X$` is the explanatory variable and `$Y$` is the dependent variable. The parameter `$b$` represents the *slope* of the line, while `$a$` is called the *intercept* (the value of `$y$` when `$x = 0$`).

For more details visit the related [wikipedia page](http://en.wikipedia.org/wiki/Simple_linear_regression).

---
---
#### Task:
The function that you have to write accepts two list/array, `$x$` and `$y$`,  representing the coordinates of the points to regress (so that, for example, the first point has coordinates (`x[0], y[0]`)).

Your function should return a tuple (in Python) or an array (any other language) of two elements: `a` (intercept) and `b` (slope) in this order.

You must round your result to the first 4 decimal digits

#### Formula:

   

`$x_i$` and `$y_i$` is `$x$` and `$y$` co-ordinate of `$i$`-th point;  
`$n$` is length of input.  

`$a =  \dfrac{\sum x_i^2\cdot \sum y_i - \sum x_i \cdot\sum x_iy_i}{n\sum x_i^2 - (\sum x_i)^2}$`

`$b =  \dfrac{n\sum x_i y_i - \sum x_i \cdot \sum y_i}{n\sum x^2_i - (\sum x_i)^2}$`
#### Examples:

```python
regressionLine([25,30,35,40,45,50], [78,70,65,58,48,42]) == (114.381, -1.4457)

regressionLine([56,42,72,36,63,47,55,49,38,42,68,60], [147,125,160,118,149,128,150,145,115,140,152,155]) == (80.7777, 1.138)
```
----

```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 regressionLine(x, y):\n    """ Return the a (intercept)\n        and b (slope) of Regression Line \n        (Y on X).\n    """\n    x2 = [float(i**2) for i in x]\n    y2 = [float(i**2) for i in y]\n    xy = [x[i]*y[i] for i in range(0,len(x))]\n    a = (sum(x2)*sum(y) - sum(x)*sum(xy))/(len(x)*sum(x2) - sum(x)**2)\n    b = (len(x)*sum(xy) - sum(x)*sum(y))/(len(x)*sum(x2) - sum(x)**2)\n    return (round(a,4),round(b,4))\n'
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'regressionLine'
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: 6868