You are given a string $s$ of even length $n$. String $s$ is binary, in other words, consists only of 0's and 1's.

String $s$ has exactly $\frac{n}{2}$ zeroes and $\frac{n}{2}$ ones ($n$ is even).

In one operation you can reverse any substring of $s$. A substring of a string is a contiguous subsequence of that string.

What is the minimum number of operations you need to make string $s$ alternating? A string is alternating if $s_i \neq s_{i + 1}$ for all $i$. There are two types of alternating strings in general: 01010101... or 10101010...


-----Input-----

The first line contains a single integer $t$ ($1 \le t \le 1000$) — the number of test cases.

The first line of each test case contains a single integer $n$ ($2 \le n \le 10^5$; $n$ is even) — the length of string $s$.

The second line of each test case contains a binary string $s$ of length $n$ ($s_i \in$ {0, 1}). String $s$ has exactly $\frac{n}{2}$ zeroes and $\frac{n}{2}$ ones.

It's guaranteed that the total sum of $n$ over test cases doesn't exceed $10^5$.


-----Output-----

For each test case, print the minimum number of operations to make $s$ alternating.


-----Example-----
Input
3
2
10
4
0110
8
11101000

Output
0
1
2



-----Note-----

In the first test case, string 10 is already alternating.

In the second test case, we can, for example, reverse the last two elements of $s$ and get: 0110 $\rightarrow$ 0101.

In the third test case, we can, for example, make the following two operations:   11101000 $\rightarrow$ 10101100;  10101100 $\rightarrow$ 10101010.

```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

ns = {"__name__": "__main__"}
for _k, _v in list(globals().items()):
    if not _k.startswith("_"):
        ns[_k] = _v
_CODE = "import sys\n\ndef input(): return sys.stdin.readline().strip()\ndef list2d(a, b, c): return [[c for j in range(b)] for i in range(a)]\ndef list3d(a, b, c, d): return [[[d for k in range(c)] for j in range(b)] for i in range(a)]\ndef list4d(a, b, c, d, e): return [[[[e for l in range(d)] for k in range(c)] for j in range(b)] for i in range(a)]\ndef ceil(x, y=1): return int(-(-x // y))\ndef INT(): return int(input())\ndef MAP(): return list(map(int, input().split()))\ndef LIST(N=None): return list(MAP()) if N is None else [INT() for i in range(N)]\ndef Yes(): print('Yes')\ndef No(): print('No')\ndef YES(): print('YES')\ndef NO(): print('NO')\nINF = 10**19\nMOD = 10**9 + 7\nEPS = 10**-10\n\ndef RLE(data):\n    from itertools import groupby\n\n    return [(x, len(list(grp))) for x, grp in groupby(data)]\n\n\ndef check(S, T):\n    A = [0] * N\n    for i in range(N):\n        if S[i] != T[i]:\n            A[i] = 1\n    \n    rle = RLE(A)\n    cnt = 0\n    for x, _ in rle:\n        if x:\n            cnt += 1\n    return cnt\n\nfor _ in range(INT()):\n    N = INT()\n    S = input()\n\n    T1 = '01' * (N//2)\n    T2 = '10' * (N//2)\n\n    ans = min(check(S, T1), check(S, T2))\n    print(ans)\n"
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

```

Measured memory_bytes: 15723