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())
for rwerwe in range(t):
	n,x = map(int,input().split())
	s = input()
	#ile x, ile x - roz, ile x - 2*roz
	z = s.count("0")
	j = s.count("1")
	roz = z - j
	d = {}
	rozn = 0
	d[0] = 0
	for i in range(n):
		if s[i] == "0":
			rozn += 1
		else:
			rozn -= 1
		d[rozn] = 0
	rozn = 0
	for i in range(n):
		if s[i] == "0":
			rozn += 1
		else:
			rozn -= 1
		d[rozn] += 1
	if roz == 0:
		try:
			wyn = d[x]
			print(-1)
		except Exception:
			print(0)
	else:
		if x > 0:
			if x > 2*n:
				x -= abs(roz)*((x-2*n)//abs(roz))
		if x < 0:
			if x < -2*n:
				x += abs(roz)*((-x-2*n)//abs(roz))
		#print(d,n,x)
		wyn = 0
		i = x
		while abs(i) <=4*n:
			try:
				wyn += d[i]
			except Exception:
				xx = 0
			i -= roz
		if x == 0:
			wyn += 1
		print(wyn)