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 sys import stdin
# def input():
#     return next(stdin)[:-1]

def main():
    def solve():

        n, x = map(int, input().split())
        ss = input()
        if ss[0] == '0':
            b = [1]
        else:
            b = [-1]
        for s in ss[1:]:
            b.append(b[-1] + (1 if s == '0' else -1))
        bc = Counter(b)
        inc = b[-1]
        if inc == 0:
            if bc[x] != 0:
                print(-1)
            else:
                print(0)
            return
        count = 0
        if (x < -n and inc > 0) or (x > n and inc < 0):
            print(0)
            return
        if inc > 0:
            if x > n:
                x = x + ((-x+n)//inc)*inc
            for i in range(x, -n-1, -inc):
                count += bc[i]
        else:
            if x < -n:
                x = x + ((-x-n)//inc)*inc
            for i in range(x, n+1, -inc):
                count +=bc[i]
        if x == 0:
            count+=1
        print(count)


    q = int(input())
    for _ in range(q):
        solve()


if __name__ == "__main__":
    main()