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:
# -*- coding: utf-8 -*-

t = int(input())
for i in range(t):
    n, x = map(int, input().split())
    s = input()
    
    c0 = 0
    c1 = 0
    posl = []
    
    for j in s:
        if j == '0':
            c0 += 1
        else:
            c1 += 1
            
        xn = c0 - c1
        posl.append(xn)
        
        
    if c1 == 0:
        if x >= 0:
            print(1)
        else:
            print(0)
        
    elif c0 == 0:
        if x <= 0:
            print(1)
        else:
            print(0)
        
    else:
        
        d = posl[-1]
        
        if d == 0:
            if x in posl:
                print(-1)
            else:
                print(0)
                
        else:
            
            def check(point, line, delta):
                if point <= line and delta > 0:
                    r = True
                elif point >= line and delta < 0:
                    r = True
                else:
                    r = False
                return r
            
            summ = 0
            
            if x == 0:
                summ += 1
                
            for p in posl:
                if check(p, x, d):
                    if x == p or (abs(x - p)) % abs(d) == 0:
                        summ += 1
            
            print(summ)