It's a Pokemon battle! Your task is to calculate the damage that a particular move would do using the following formula (not the actual one from the game):

Where:

* attack = your attack power
* defense = the opponent's defense
* effectiveness = the effectiveness of the attack based on the matchup (see explanation below)

Effectiveness:

Attacks can be super effective, neutral, or not very effective depending on the matchup. For example, water would be super effective against fire, but not very effective against grass.

* Super effective: 2x damage
* Neutral: 1x damage
* Not very effective: 0.5x damage

To prevent this kata from being tedious, you'll only be dealing with four types: `fire`, `water`, `grass`, and `electric`.  Here is the effectiveness of each matchup:

* `fire > grass`
* `fire < water`
* `fire = electric`

* `water < grass`
* `water < electric`

* `grass = electric`

For this kata, any type against itself is not very effective. Also, assume that the relationships between different types are symmetric (if `A` is super effective against `B`, then `B` is not very effective against `A`).

The function you must implement takes in:
1. your type
2. the opponent's type
3. your attack power
4. the opponent's defense

```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 = 'from math import ceil\n\nD = {"fire": "grass", "water": "fire", "grass": "water", "electric": "water"}\n\ndef calculate_damage(a, b, n, m):\n    return 50 * n / m * (2 if D[a] == b else 0.5 if D[b] == a or a == b else 1)'
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'calculate_damage'
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: 5492