The prime numbers are not regularly spaced. For example from `2` to `3` the gap is `1`.
From `3` to `5` the gap is `2`. From `7` to `11` it is `4`.
Between 2 and 50 we have the following pairs of 2-gaps primes:
`3-5, 5-7, 11-13, 17-19, 29-31, 41-43`

A prime gap of length n is a run of n-1 consecutive composite numbers between two **successive** primes (see: http://mathworld.wolfram.com/PrimeGaps.html).

We will write a function gap with parameters:

`g` (integer >= 2) which indicates the gap we are looking for

`m` (integer > 2) which gives the start of the search (m inclusive)

`n` (integer >= m) which gives the end of the search (n inclusive)

In the example above `gap(2, 3, 50)` will return `[3, 5] or (3, 5) or {3, 5}` which is the first pair between 3 and 50 with a 2-gap.

So this function should return the **first** pair of two prime numbers spaced with a gap of `g`
between the limits `m`, `n` if these numbers exist otherwise `nil or null or None or Nothing` (depending on the language). 

In C++ return in such a case `{0, 0}`. In F# return `[||]`. In Kotlin return `[]`

#Examples:
`gap(2, 5, 7) --> [5, 7] or (5, 7) or {5, 7}`

`gap(2, 5, 5) --> nil. In C++ {0, 0}. In F# [||]. In Kotlin return `[]`

`gap(4, 130, 200) --> [163, 167] or (163, 167) or {163, 167}`

([193, 197] is also such a 4-gap primes between 130 and 200 but it's not the first pair)

`gap(6,100,110) --> nil or {0, 0}` : between 100 and 110 we have `101, 103, 107, 109` but `101-107`is not a
6-gap because there is `103`in between and `103-109`is not a 6-gap because there is `107`in between.

# Note for Go
For Go: nil slice is expected when there are no gap between m and n.
Example: gap(11,30000,100000) --> nil

#Ref
https://en.wikipedia.org/wiki/Prime_gap

```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 = 'primes = []\n\ndef is_prime(a):\n    if a in primes: \n        return True\n    if a < 2: return False\n    for x in range(2, int(a**0.5) + 1):\n        if a % x == 0:\n            return False\n    primes.append(a)\n    return True\n\ndef gap(g, m, n):\n    p0 = 0\n    if m % 2 == 0: m += 1\n    for i in range(m,n+1,2):\n        if is_prime(i):\n            if p0 == 0: p0 = i\n            elif i-p0 == g: return [p0,i]\n            else: p0 = i; continue\n    return None\n'
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'gap'
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: 5816