Problem: You are given string s of length n consisting of 0-s and 1-s. You build an infinite string t as a concatenation of an infinite number of strings s, or t = ssss ... For example, if s = 10010, then t = 100101001010010...

Calculate the number of prefixes of t with balance equal to x. The balance of some string q is equal to cnt_{0, q} - cnt_{1, q}, where cnt_{0, q} is the number of occurrences of 0 in q, and cnt_{1, q} is the number of occurrences of 1 in q. The number of such prefixes can be infinite; if it is so, you must say that.

A prefix is a string consisting of several first letters of a given string, without any reorders. An empty prefix is also a valid prefix. For example, the string "abcd" has 5 prefixes: empty string, "a", "ab", "abc" and "abcd".

Input

The first line contains the single integer T (1 ≤ T ≤ 100) — the number of test cases.

Next 2T lines contain descriptions of test cases — two lines per test case. The first line contains two integers n and x (1 ≤ n ≤ 10^5, -10^9 ≤ x ≤ 10^9) — the length of string s and the desired balance, respectively.

The second line contains the binary string s (|s| = n, s_i ∈ \{0, 1\}).

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

Output

Print T integers — one per test case. For each test case print the number of prefixes or -1 if there is an infinite number of such prefixes.

Example

Input


4
6 10
010010
5 3
10101
1 0
0
2 0
01


Output


3
0
1
-1

Note

In the first test case, there are 3 good prefixes of t: with length 28, 30 and 32.

Solution (in PYTHON3):

Solution:
from collections import Counter
from itertools import accumulate

def go():
    n, x = map(int,input().split())
    s = map(int,input())
    a = accumulate(s)
    a = [z-2*o for z,o in zip(range(1,n+1),a)]
    # print (list(a))
    c = Counter(a)
    if a[-1]==0:
        if x in c:
            return -1
        else:
            return 0
    elif a[-1]>0:
        result = 0 if x!=0 else 1
        # c[x] + c[x-s[-1]] + c[x-s[-1]-s[-1]]
        for v,cc in c.items():
            if v<=x and v%a[-1] == x%a[-1]:
                result += cc
        return result
    elif a[-1]<0:
        result = 0 if x!=0 else 1
        # c[x] + c[x-s[-1]] + c[x-s[-1]-s[-1]]
        for v,cc in c.items():
            if v>=x and v%a[-1] == x%a[-1]:
                result += cc
        return result

t = int(input())
for _ in range(t):
    print (go())