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 JAVA):

Solution:
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.InputMismatchException;
import java.util.*;
import java.io.*;
public class Main{
public static class InputReader {
    private InputStream stream;
    private byte[] buf = new byte[1024];
    private int curChar;
    private int numChars;
    private InputReader.SpaceCharFilter filter;
    private BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
 
    public InputReader(InputStream stream) {
        this.stream = stream;
    }
 
    public int read() {
        if (numChars==-1)
            throw new InputMismatchException();
 
        if (curChar >= numChars) {
            curChar = 0;
            try {
                numChars = stream.read(buf);
            }
            catch (IOException e) {
                throw new InputMismatchException();
            }
 
            if(numChars <= 0)
                return -1;
        }
        return buf[curChar++];
    }
 
    public String nextLine() {
        String str = "";
        try {
            str = br.readLine();
        }
        catch (IOException e) {
            e.printStackTrace();
        }
        return str;
    }
    public int nextInt() {
        int c = read();
 
        while(isSpaceChar(c))
            c = read();
 
        int sgn = 1;
 
        if (c == '-') {
            sgn = -1;
            c = read();
        }
 
        int res = 0;
        do {
            if(c<'0'||c>'9')
                throw new InputMismatchException();
            res *= 10;
            res += c - '0';
            c = read();
        }
        while (!isSpaceChar(c));
 
        return res * sgn;
    }
 
    public long nextLong() {
        int c = read();
        while (isSpaceChar(c))
            c = read();
        int sgn = 1;
        if (c == '-') {
            sgn = -1;
            c = read();
        }
        long res = 0;
 
        do {
            if (c < '0' || c > '9')
                throw new InputMismatchException();
            res *= 10;
            res += c - '0';
            c = read();
        }
        while (!isSpaceChar(c));
        return res * sgn;
    }
 
    public double nextDouble() {
        int c = read();
        while (isSpaceChar(c))
            c = read();
        int sgn = 1;
        if (c == '-') {
            sgn = -1;
            c = read();
        }
        double res = 0;
        while (!isSpaceChar(c) && c != '.') {
            if (c == 'e' || c == 'E')
                return res * Math.pow(10, nextInt());
            if (c < '0' || c > '9')
                throw new InputMismatchException();
            res *= 10;
            res += c - '0';
            c = read();
        }
        if (c == '.') {
            c = read();
            double m = 1;
            while (!isSpaceChar(c)) {
                if (c == 'e' || c == 'E')
                    return res * Math.pow(10, nextInt());
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                m /= 10;
                res += (c - '0') * m;
                c = read();
            }
        }
        return res * sgn;
    }
 
    public String readString() {
        int c = read();
        while (isSpaceChar(c))
            c = read();
        StringBuilder res = new StringBuilder();
        do {
            res.appendCodePoint(c);
            c = read();
        }
        while (!isSpaceChar(c));
 
        return res.toString();
    }
 
    public boolean isSpaceChar(int c) {
        if (filter != null)
            return filter.isSpaceChar(c);
        return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }
 
    public String next() {
        return readString();
    }
 
    public interface SpaceCharFilter {
        public boolean isSpaceChar(int ch);
    }
}
    
	static void mergeSort(int[] input,int start,int end)
    {
        if(start>end || start==end)
            return;
        int mid=(start+end)/2;
        mergeSort(input,start,mid);
        mergeSort(input,mid+1,end);
        
        merge(input,start,end);
        
    }
    static void merge(int input[],int start,int end)
    {
        int sorted[] = new int[end-start+1];
        int mid=(start+end)/2;
        int i=start,j=mid+1,count=0;
        
        while(i<=mid && j<=end)
        {
            if(input[i]>input[j])
            {
                sorted[count]=input[j];
                j++;
                count++;
            }
            else
            {
                sorted[count]=input[i];
                i++;
                count++;
            }
        }
        if(i>mid)
        {
            while(j<=end)
            {
                sorted[count]=input[j];
                j++;
                count++;
            }
        }
        else
        {
            while(i<=mid)
            {
                sorted[count]=input[i];
                i++;
                count++;
            }
        }
        for(i=start;i<=end;i++)
        {
            input[i]=sorted[i-start];
        }
    }
 
    public static void main(String[] args) 
    { 
       InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader sc = new InputReader(inputStream);
        PrintWriter w = new PrintWriter(outputStream);
       int t=sc.nextInt();
		while(t-->0) {
			int n=sc.nextInt();
			int x=sc.nextInt();
			String s=sc.next();
			int sum=0;
			int ans=0,curr_sum=0;
			for(int i=0;i<n;++i) {
				if(s.charAt(i)=='0')
					++sum;
				else
					--sum;
			}
			for(int i=0;i<n;++i) {
				
				if( sum == 0 ) {
					if(curr_sum==x) {
						ans=-1;
						break;
					}
				}
				else {
					if( (Math.abs(x-curr_sum))%Math.abs(sum)==0 ) {
						if( (x-curr_sum)/sum >=0 )
							++ans;
					}
				}
				if(s.charAt(i)=='0') ++curr_sum;
				else --curr_sum;
			}
			w.println(ans);
			
			
		}
	w.close();
	}
 }