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:
t = int(input())
while t:
	n,k = list(map(int,input().split()))
	bs = str(input())
	pref = [0 for i in range(n)]
	for i in range(n):
		if(i==0):
			if(bs[i])=='0':
				pref[i]=1
			else:
				pref[i]=-1
		else:
			if(bs[i])=='0':
				pref[i] = pref[i-1]+1
			else:
				pref[i] = pref[i-1]-1
	ans = 0
	last = pref[-1]
	if k==0:
		ans+=1
	if last!=0:
		for i in range(len(pref)):
			tt = (k - pref[i])//last
			if(tt==0 and last==0):
				ans=-1
				break
			if(tt*last+pref[i]==k and tt>=0):
				ans+=1
		print(ans)
	else:
		for i in range(len(pref)):
			if(pref[i]==k):
				ans=-1
				break
		print(ans)
	t-=1