DNA is a biomolecule that carries genetic information. It is composed of four different building blocks, called nucleotides: adenine (A), thymine (T), cytosine (C) and guanine (G). Two DNA strands join to form a double helix, whereby the nucleotides of one strand bond to the nucleotides of the other strand at the corresponding positions. The bonding is only possible if the nucleotides are complementary: A always pairs with T, and C always pairs with G.

Due to the asymmetry of the DNA, every DNA strand has a direction associated with it. The two strands of the double helix run in opposite directions to each other, which we refer to as the 'up-down' and the 'down-up' directions.

Write a function `checkDNA` that takes in two DNA sequences as strings, and checks if they are fit to form a fully complementary DNA double helix. The function should return a Boolean `true` if they are complementary, and `false` if there is a sequence mismatch (Example 1 below).

Note:

- All sequences will be of non-zero length, and consisting only of `A`, `T`, `C` and `G` characters.
- All sequences **will be given in the up-down direction**.
- The two sequences to be compared can be of different length. If this is the case and one strand is entirely bonded by the other, and there is no sequence mismatch between the two (Example 2 below), your function should still return `true`.
- If both strands are only partially bonded (Example 3 below), the function should return `false`.

Example 1:

Example 2:

Example 3:

---
#### If you enjoyed this kata, check out also my other DNA kata: [**Longest Repeated DNA Motif**](http://www.codewars.com/kata/longest-repeated-dna-motif)

```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 check_DNA(seq1, seq2):\n if len(seq1) < len(seq2): seq1, seq2 = seq2, seq1\n seq2 = seq2[::-1].replace('C','g').replace('G','c').replace('T','a').replace('A','t').upper()\n return seq1.find(seq2) >= 0"
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'check_DNA'
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: 5602