# Challenge : 

Write a function that takes a single argument `n` that is a string representation of a simple mathematical expression and evaluates it as a floating point value. 

# Commands : 
- positive or negative decimal numbers
- `+, -, *, /, ( / ).`

---

Expressions use [infix notation](https://en.wikipedia.org/wiki/Infix_notation). 

# Evaluation : 

Operators should be evaluated in the order they appear and not as in `BODMAS`, though brackets __should__ be correctly observed. 

The function should return the correct result for any possible expression of this form.

# Note : 

- All given input will be valid.
- It will consist entirely of numbers or one of the operators.
- Parentheses will alway be matched.
- Use of `eval` or its equivalent is forbidden
- use of `exec` is forbidden (Python) 
- Use of `Function` or any of their (Function, eval) equivalent is also forbidden.
- Using `require` is also forbidden. (`import` for python)
- Using more than 7 (8 for python) lines is also forbidden.
- Using more than 260 (JS) / 240 (python) characters is also forbidden.
- Having more than 100 chars per line is forbidden.
- Having more than 6 semi-colons is forbidden

and that is about it.

--- 

# Examples : 

    e("2*3*4*5+99")               ---> 219
    e("2*3*4*5+99*321-12312312")  ---> -12242013
    e("1-2*2/2*2-1*7+3")          ---> -18

---

```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 e(s):return f([*s,'+'])\ndef f(s,r=0,o=0,x='',c=0):\n while s and')'!=c:\n  c=s.pop(0);i='+-*/)('.find(c)\n  if c=='-'>x or i<0:x+=c\n  elif c=='(':x=str(f(s))\n  elif i>-1:a=float(x);r=[r+a,r-a,r*a,r/a][o];o=i;x=''\n return r"
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'e'
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: 5844