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>
#pragma GCC optimize(3, "Ofast", "inline")
using namespace std;
const long long maxn = (long long)1e6 + 5;
const long long mod = 1000000007;
const long long inf = 0x3f3f3f3f;
signed main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long T;
  cin >> T;
  while (T--) {
    unordered_map<long long, long long> mp;
    long long n, x;
    cin >> n >> x;
    string s;
    cin >> s;
    long long balmax = -1e6, balmin = 1e6, bal = 0;
    for (auto &i : s) {
      if (i == '0')
        ++bal;
      else
        --bal;
      ++mp[bal];
      balmax = max(balmax, bal);
      balmin = min(balmin, bal);
    }
    if (bal == 0) {
      if (x >= balmin && x <= balmax)
        cout << -1 << '\n';
      else
        cout << 0 << '\n';
      continue;
    }
    long long balt = 0;
    long long ans = 0;
    if (x == 0) ++ans;
    for (auto &i : s) {
      if (i == '0')
        ++balt;
      else
        --balt;
      if ((x - balt) * bal >= 0 && (x - balt) % bal == 0) ++ans;
    }
    cout << ans << '\n';
  }
  return 0;
}