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
import math
from collections import defaultdict as dd
mod=1000000007
T=1
T=int(sys.stdin.readline())
for _ in range(T):
    n,k=map(int,input().split())
    s=input()
    x=0
    d=dd(int)
    for i in s:
        if i=='0':
            x+=1
        else:
            x-=1
        d[x]+=1
    if x==0:
        if d[k]:
            print(-1)
        else:
            print(0)
        continue
    c=0
    if(k==0):
        c=1
    if(x>0):
        rem=k%x
        for i in d:
            if(i<=k and i%x==rem):
                c+=d[i]
        print(c)
    else:
        mp=dd(int)
        y=0
        k=-k
        for i in s:
            if i=='1':
                y+=1
            else:
                y-=1
            mp[y]+=1
        rem=k%y
        for i in mp:
            if(i<=k and i%y==rem):
                c+=mp[i]
        print(c)