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:
import collections

if __name__=='__main__':
    for i in range(int(input())):
        n,x=map(int,input().split())
        sum=0
        cnt=0
        s=input()
        a=collections.defaultdict(lambda :0)
        '''
        for j in a:
            print(j)
        '''
        for j in s:
            if j=='0':
                sum=sum+1
            else:
                sum=sum-1
            a[sum]=a[sum]+1
            
            #print(str(j)+ "pe sum:"+ str(sum)+ "and a["+str(sum)+"]="+str(a[sum]))
        '''
        for i in a:
            if ((x-i)%sum==0) and sum>0:
                cnt=cnt+a[i]
            elif(sum==0):
                if x in a:
                    cnt
        '''
        if(x==0):
            cnt=1
        if(sum>0):
            for i in a:
                if ((x-i)%sum==0) and (x-i)>=0:
                    cnt=cnt+a[i]
        elif(sum==0):
            for i in a:
                if(i==x):
                    cnt=-1
                    #print(i,a[i],cnt)
        elif(sum<0):
            for i in a:
                if ((i-x)%(sum*(-1))==0) and i-x>=0:
                    cnt=cnt+a[i]
                    #print(i,a[i],cnt)
            
        print(cnt)