# Task
 In the Land Of Chess, bishops don't really like each other. In fact, when two bishops happen to stand on the same diagonal, they immediately rush towards the opposite ends of that same diagonal.

 Given the initial positions (in chess notation) of two bishops, `bishop1` and `bishop2`, calculate their future positions. Keep in mind that bishops won't move unless they see each other along the same diagonal.

# Example

 For `bishop1 = "d7" and bishop2 = "f5"`, the output should be `["c8", "h3"]`.

 ![](https://codefightsuserpics.s3.amazonaws.com/tasks/bishopDiagonal/img/ex_1.jpg?_tm=1473766087137)

 For `bishop1 = "d8" and bishop2 = "b5"`, the output should be `["b5", "d8"]`.

 The bishops don't belong to the same diagonal, so they don't move.

 ![](https://codefightsuserpics.s3.amazonaws.com/tasks/bishopDiagonal/img/ex_2.jpg?_tm=1473766087425)

# Input/Output


 - `[input]` string `bishop1`

    Coordinates of the first bishop in chess notation.


 - `[input]` string `bishop2`

    Coordinates of the second bishop in the same notation.


 - `[output]` a string array

    Coordinates of the bishops in lexicographical order after they check the diagonals they stand on.

```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 bishop_diagonal(bishop1, bishop2):\n    letters = ' abcdefgh'\n    x1, y1 = int(letters.index(bishop1[0])), int(bishop1[1])\n    x2, y2 = int(letters.index(bishop2[0])), int(bishop2[1])\n    if abs(x1 - x2) == abs(y1 - y2):\n        xdir = (x1 - x2) // abs(x1 - x2)\n        ydir = (y1 - y2) // abs(y1 - y2)\n        while 1 < x1 < 8 and 1 < y1 < 8:\n            x1 += xdir\n            y1 += ydir\n        while 1 < x2 < 8 and 1 < y2 < 8:\n            x2 -= xdir\n            y2 -= ydir\n    return sorted([letters[x1] + str(y1), letters[x2] + str(y2)])"
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'bishop_diagonal'
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: 6270