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 getans():
    n,x = map(int,input().split(" "))
    s = input()
    a = []
    for i in s:
        if ( i == "0" ):
            a.append(1)
        else:
            a.append(-1)
    b = [a[0]]
    for i in range(1,len(a)):
        b.append(b[-1] + a[i])

    step = b[-1]
    #print (b,step)
    ans = 0
    if ( x == 0 ): ans = ans + 1
    if ( step == 0 ):
        for i in b:
            if ( x == i ): return -1
        return ans
    elif ( step < 0 ):
        step = -step
        for i in b:
            if ( i >= x and (i - x) % step == 0 ): ans = ans + 1
    else:
        for i in b:
            if ( i <= x and (x - i) % step == 0 ): ans = ans + 1

    return ans
    

t = int(input())
for i in range(t):
    print (getans())