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 math
#from functools import lru_cache
#import heapq
#from collections import defaultdict
#from collections import Counter
#from collections import deque
#from sys import stdout
#from sys import setrecursionlimit
#setrecursionlimit(10**7)
from sys import stdin
input = stdin.readline

INF = 10**9 + 7
MAX = 10**7 + 7
MOD = 10**9 + 7

for Ti in range(int(input().strip())):
    n, x = [int(x) for x in input().strip().split()]
    s = input().strip()
    a = [0]
    c = 0
    for si in s:
        if(si=='0'):
            c+=1
        else:
            c-=1
        a.append(c)
    slen = len(s)
    cyc = a[slen] - a[0]
    ans = 0
    for i in range(1, slen+1):
        if(not cyc and x==a[i]):
            ans += 1
        if(cyc and (x - a[i])%cyc == 0 and (x-a[i])//cyc>=0):
            ans += 1
    if(ans>0 and not cyc):
        print('-1')
    else:
        if(a[0] == x): ans += 1
        print(ans)