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 CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false), cin.tie(NULL);
  int n;
  int t;
  cin >> t;
  int ans = 0;
  while (t--) {
    int m;
    cin >> n >> m;
    string s;
    ans = 0;
    cin >> s;
    int c1 = 0, c0 = 0;
    for (auto it : s) {
      if (it == '0')
        c0++;
      else
        c1++;
    }
    if (c0 == c1) {
      c1 = 0;
      c0 = 0;
      for (auto it : s) {
        if (it == '0')
          c0++;
        else
          c1++;
        if (c0 - c1 == m) {
          ans++;
        }
      }
      if (ans) {
        cout << -1 << endl;
      } else {
        cout << 0 << endl;
      }
      continue;
    }
    long long int x = c0 - c1;
    c0 = 0;
    c1 = 0;
    if (m == 0) ans++;
    for (auto it : s) {
      if (it == '1')
        c1++;
      else
        c0++;
      int dd = c0 - c1;
      long long int nd = m - dd;
      if (nd % x == 0 and nd * x >= 0) {
        ans++;
      }
    }
    cout << ans << endl;
  }
}