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 sys;input=sys.stdin.readline
# from collections import defaultdict
from itertools import accumulate
# from decimal import *
# import math
# getcontext().prec = 50
# s = input().strip()
# n = int(input())
# lis = list(map(int,input().split()))
# x,y = map(int,input().split())
# chars = 'abcdefghijklmnopqrstuvwxyz'
# import heapq
# def gcd(a,b):
#     return gcd (b, a % b) if b else a

def solve():
    n,x = map(int,input().split())
    s = input().strip()
    init = list(accumulate([-1 if i =='1' else 1 for i in s]))
    count = 0
    if init[-1]==0:
        if x in init:
            print(-1)
            return
        else:
            print(0)
            return
    for i in init:
        if (x-i)%init[-1]==0:
            if (x-i)//init[-1]>=0:
                count+=1
    if x==0:
        count+=1
    print(count)

    
    
                
                
            
        
        
    
# solve()
for _ in range(int(input())):
    solve()