Given an array nums of positive integers, return the longest possible length of an array prefix of nums, such that it is possible to remove exactly one element from this prefix so that every number that has appeared in it will have the same number of occurrences.
If after removing one element there are no remaining elements, it's still considered that every appeared number has the same number of ocurrences (0).
 
Example 1:
Input: nums = [2,2,1,1,5,3,3,5]
Output: 7
Explanation: For the subarray [2,2,1,1,5,3,3] of length 7, if we remove nums[4]=5, we will get [2,2,1,1,3,3], so that each number will appear exactly twice.

Example 2:
Input: nums = [1,1,1,2,2,2,3,3,3,4,4,4,5]
Output: 13

Example 3:
Input: nums = [1,1,1,2,2,2]
Output: 5

Example 4:
Input: nums = [10,2,8,9,3,8,1,5,2,3,7,6]
Output: 8

 
Constraints:

2 <= nums.length <= 10^5
1 <= nums[i] <= 10^5

```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 = 'class Solution:\n    # hashmap\n    # review\n    def maxEqualFreq(self, nums: List[int]) -> int:\n        count = collections.defaultdict(int)\n        freq = collections.defaultdict(int)\n\n        # for test case [1,1,1,2,2,2] , the ans is 5, [1,1,1,2,2], len=5, you can remove 1, then 1 and 2 occur 2 times\n        # we will get count {1:3, 2:3}\n        # for freq: we would get {1:2, 2:2, 3: 2}, notice we loop from left to right, so we would get\n        # freq : {1:1}, {1:1, 2:1}, {1:1,2:1,3:1}, {1:2,2:1,3:1}, {1:2,2:2,3:1},{1:2,2:2,3:2}\n        for n in nums:\n            count[n] += 1\n            freq[count[n]] += 1\n\n        for i in range(len(nums) - 1, 0, -1):\n            # 2 case, case 1 , keep i, then you have to remove another on from 0 -- i-1\n            # for test case [1,1,1,2,2,2], at index i = 5, 3 * 2 = 6 != 5, because we need to remove one element if we\n            # want to keep ith element\n            # but i = 4,  count[2] = 2, freq[2] = 2, 2 * 2 = 4, ie, when i = 4, total 5 elements, remove 1 ele, remain 4.\n            # notice we need to return ri+1, because w need to prefix length, which include the removed element\n\n            # this means from 0->i , each num appear equal times, then we just need to remove i+1\n            if count[nums[i]] * freq[count[nums[i]]] == i:\n                return i + 1\n            freq[count[nums[i]]] -= 1\n            count[nums[i]] -= 1\n\n            if count[nums[i - 1]] * freq[count[nums[i - 1]]] == i:\n                return i + 1\n\n        return 1\n\n\n'
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'maxEqualFreq'
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