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.*;
import java.math.*;
import java.util.*;

public class Main {
	private static final int N_MAX = 100000;

	public static void solveCase(FastIO io, int testCase) {
		int N = io.nextInt();
		int X = io.nextInt();
		char[] S = io.nextLine().toCharArray();

		int[] prefix = new int[N + 1];
		CountMap<Integer> cm = new CountMap<>();
		for (int i = 0; i < N; ++i) {
			int add = (S[i] == '0') ? 1 : -1;
			prefix[i + 1] = prefix[i] + add;
			cm.addCount(prefix[i], 1);
		}

		if (prefix[N] == 0) {
			if (cm.getCount(X) > 0) {
				io.println(-1);
			} else {
				io.println(0);
			}
			return;
		}

		int total = 0;
		for (Map.Entry<Integer, Integer> kvp : cm.entrySet()) {
			int num = kvp.getKey();
			int freq = kvp.getValue();
			int diff = X - num;
			if (diff % prefix[N] != 0) {
				continue;
			}
			int repeats = diff / prefix[N];
			if (repeats < 0) {
				continue;
			}
			total += freq;
		}
		io.println(total);
	}

	private static class CountMap<T> extends HashMap<T, Integer> {
		public int getCount(T k) {
			return getOrDefault(k, 0);
		}

		public void addCount(T k, int v) {
			int next = getCount(k) + v;
			if (next == 0) {
				remove(k);
			} else {
				put(k, next);
			}
		}
	}

	public static void solve(FastIO io) {
		int T = io.nextInt();

		for (int t = 0; t < T; ++t) {
			solveCase(io, t);
		}
	}

	public static class FastIO {
		private InputStream reader;
		private PrintWriter writer;

		private byte[] buf = new byte[1024];
		private int curChar;
		private int numChars;

		public FastIO(InputStream r, OutputStream w) {
			reader = r;
			writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(w)));
		}

		public int read() {
			if (numChars == -1)
				throw new InputMismatchException();
			if (curChar >= numChars) {
				curChar = 0;
				try {
					numChars = reader.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (numChars <= 0)
					return -1;
			}
			return buf[curChar++];
		}

		public String nextLine() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isEndOfLine(c));
			return res.toString();
		}

		public String nextString() {
			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 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 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;
		}

		// TODO: read this byte-by-byte like the other read functions.
		public double nextDouble() {
			return Double.parseDouble(nextString());
		}

		public int[] nextIntArray(int n) {
			return nextIntArray(n, 0);
		}

		public int[] nextIntArray(int n, int off) {
			int[] arr = new int[n + off];
			for (int i = 0; i < n; i++) {
				arr[i + off] = nextInt();
			}
			return arr;
		}

		public long[] nextLongArray(int n) {
			return nextLongArray(n, 0);
		}

		public long[] nextLongArray(int n, int off) {
			long[] arr = new long[n + off];
			for (int i = 0; i < n; i++) {
				arr[i + off] = nextLong();
			}
			return arr;
		}

		private boolean isSpaceChar(int c) {
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}

		private boolean isEndOfLine(int c) {
			return c == '\n' || c == '\r' || c == -1;
		}

		public void print(Object... objects) {
			for (int i = 0; i < objects.length; i++) {
				if (i != 0) {
					writer.print(' ');
				}
				writer.print(objects[i]);
			}
		}

		public void println(Object... objects) {
			print(objects);
			writer.println();
		}

		public void printArray(int[] arr) {
			for (int i = 0; i < arr.length; i++) {
				if (i != 0) {
					writer.print(' ');
				}
				writer.print(arr[i]);
			}
		}

		public void printArray(long[] arr) {
			for (int i = 0; i < arr.length; i++) {
				if (i != 0) {
					writer.print(' ');
				}
				writer.print(arr[i]);
			}
		}

		public void printlnArray(int[] arr) {
			printArray(arr);
			writer.println();
		}

		public void printlnArray(long[] arr) {
			printArray(arr);
			writer.println();
		}

		public void printf(String format, Object... args) {
			print(String.format(format, args));
		}

		public void flush() {
			writer.flush();
		}
	}

	public static void main(String[] args) {
		FastIO io = new FastIO(System.in, System.out);
		solve(io);
		io.flush();
	}
}