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:
for t in range(int(input())):
      n,x=map(int,input().split())
      s=input()
      if(s[0]=="1"):
            a=[-1]
      else:
            a=[1]
      for i in range(1,n):
            if(s[i]=="0"):
                  a.append(a[i-1]+1)
            else:
                  a.append(a[i-1]-1)
      g=0
      for i in range(n):
            if(a[i]==x):
                  g=1
                  break
      if(g==1 and a[n-1]==0):
            print(-1)
      elif(a[n-1]==0):
            print(0)
      else:
            tot=0
            if(x==0):
                  tot=1
            for i in range(n):
                  if(a[i]==x):
                        tot+=1
                  else:
                        g=x-a[i]
                        if((g%a[n-1] == 0)and(g*a[n-1] >=0)):
                              tot+=1
            print(tot)