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:
def calc(s, x):
    orig = [-1]
    if s[0] == '0':
        orig = [1]
    for i in range(1, len(s)):
        if s[i] == '0':
            orig.append(orig[-1] + 1)
        else:
            orig.append(orig[-1] - 1)
    diff, cum = [], orig[-1]
    res = 0
    if x == 0:
        res = 1
    for i in range(len(s)):
        if orig[i] == x:
            res += 1
        if s[i] == '0':
            cum += 1
        else:
            cum -= 1
        diff = cum - orig[i]
        if diff == 0 and orig[i] == x:
            return -1
        elif diff == 0 and orig[i] != x:
            continue
        n = (x - orig[i]) / diff
        if n % 1 == 0 and n > 0:
            res += 1
    return res

if __name__ == '__main__':
    N = int(input())
    cases = []
    for _ in range(N):
        _, x = map(int, input().split())
        s = input()
        cases.append([s, x])
    for s, x in cases:
        print(calc(s, x))