description: Theofanis has a string s_1 s_2 ... s_n and a character c. He wants to make all characters of the string equal to c using the minimum number of operations.
  
  In one operation he can choose a number x (1 ≤ x ≤ n) and for every position i, where i is not divisible by x, replace s_i with c. 
  
  Find the minimum number of operations required to make all the characters equal to c and the x-s that he should use in his operations.
  
  Input
  
  The first line contains a single integer t (1 ≤ t ≤ 10^4) — the number of test cases.
  
  The first line of each test case contains the integer n (3 ≤ n ≤ 3 ⋅ 10^5) and a lowercase Latin letter c — the length of the string s and the character the resulting string should consist of.
  
  The second line of each test case contains a string s of lowercase Latin letters — the initial string.
  
  It is guaranteed that the sum of n over all test cases does not exceed 3 ⋅ 10^5.
  
  Output
  
  For each test case, firstly print one integer m — the minimum number of operations required to make all the characters equal to c.
  
  Next, print m integers x_1, x_2, ..., x_m (1 ≤ x_j ≤ n) — the x-s that should be used in the order they are given.
  
  It can be proved that under given constraints, an answer always exists. If there are multiple answers, print any.
  
  Example
  
  Input
  
  
  3
  4 a
  aaaa
  4 a
  baaa
  4 b
  bzyx
  
  
  Output
  
  
  0
  1
  2
  2 
  2 3
  
  Note
  
  Let's describe what happens in the third test case: 
  
    1. x_1 = 2: we choose all positions that are not divisible by 2 and replace them, i. e. bzyx → bzbx; 
    2. x_2 = 3: we choose all positions that are not divisible by 3 and replace them, i. e. bzbx → bbbb. 
solution: 
  
  
  public class Main {
  
  	public static void main(String[] args) {
  		new Main();
  	}
  
  	public Main() {
  		FastScanner fs = new FastScanner();
  		java.io.PrintWriter out = new java.io.PrintWriter(System.out);
  		solve(fs, out);
  		out.flush();
  	}
  
  	public void solve(FastScanner fs, java.io.PrintWriter out) {
  		int t = fs.nextInt();
  		test: while(t --> 0) {
  			int n = fs.nextInt();
  			char c = fs.nextChar();
  			char[] s = fs.next().toCharArray();
  			int ng = 0;
  			for (char i : s) if (i != c) ++ ng;
  			if (ng == 0) {
  				out.println(0);
  				continue test;
  			}
  			for (int i = 1;i <= n;++ i) {
  				int count = 0;
  				for (int j = i;j <= n;j += i) {
  					if (s[j - 1] != c) ++ count;
  				}
  				if (count == 0) {
  					out.println(1);
  					out.println(i);
  					continue test;
  				}
  			}
  			out.println(2);
  			out.println(n - 1 + " " + n);
  		}
  	}
  
  	final int MOD = 1_000_000_007;
  	int plus(int n, int m) {
  		int sum = n + m;
  		if (sum >= MOD) sum -= MOD;
  		return sum;
  	}
  	int minus(int n, int m) {
  		int sum = n - m;
  		if (sum < 0) sum += MOD;
  		return sum;
  	}
  	int times(int n, int m) {
  		return (int)((long)n * m % MOD);
  	}
  	int divide(int n, int m) {
  		return times(n, IntMath.pow(m, MOD - 2, MOD));
  	}
  	int[] fact, invf;
  	void calc(int len) {
  		len += 2;
  		fact = new int[len];
  		invf = new int[len];
  		fact[0] = fact[1] = invf[0] = invf[1] = 1;
  		for (int i = 2;i < fact.length;++ i) fact[i] = times(fact[i - 1], i);
  		invf[len - 1] = divide(1, fact[len - 1]);
  		for (int i = len - 1;i > 1;-- i) invf[i - 1] = times(i, invf[i]);
  	}
  	int comb(int n, int m) {
  		if (n < m) return 0;
  		return times(fact[n], times(invf[n - m], invf[m]));
  	}
  }
  
  class FastScanner {
  
  	private final java.io.InputStream in = System.in;
  	private final byte[] buffer = new byte[8192];
  	private int ptr = 0;
  	private int buflen = 0;
  
  	private boolean hasNextByte() {
  		if (ptr < buflen) return true;
  		ptr = 0;
  		try {
  			buflen = in.read(buffer);
  		} catch (java.io.IOException e) {
  			e.printStackTrace();
  		}
  		return buflen > 0;
  	}
  
  	private byte readByte() {
  		return hasNextByte() ? buffer[ptr++ ] : -1;
  	}
  
  	private static boolean isPrintableChar(byte c) {
  		return 32 < c || c < 0;
  	}
  
  	private static boolean isNumber(int c) {
  		return '0' <= c && c <= '9';
  	}
  
  	public boolean hasNext() {
  		while (hasNextByte() && !isPrintableChar(buffer[ptr]))
  			ptr++ ;
  		return hasNextByte();
  	}
  
  	public String next() {
  		if (!hasNext()) throw new java.util.NoSuchElementException();
  		StringBuilder sb = new StringBuilder();
  		byte b;
  		while (isPrintableChar(b = readByte()))
  			sb.appendCodePoint(b);
  		return sb.toString();
  	}
  
  	public final char nextChar() {
  		if (!hasNext()) throw new java.util.NoSuchElementException();
  		return (char)readByte();
  	}
  
  	public final long nextLong() {
  		if (!hasNext()) throw new java.util.NoSuchElementException();
  		long n = 0;
  		try {
  			byte b = readByte();
  			if (b == '-') {
  				while (isNumber(b = readByte()))
  					n = n * 10 + '0' - b;
  				return n;
  			} else if (!isNumber(b)) throw new NumberFormatException();
  			do
  				n = n * 10 + b - '0';
  			while (isNumber(b = readByte()));
  		} catch (java.util.NoSuchElementException e) {}
  		return n;
  	}
  
  	public final int nextInt() {
  		if (!hasNext()) throw new java.util.NoSuchElementException();
  		int n = 0;
  		try {
  			byte b = readByte();
  			if (b == '-') {
  				while (isNumber(b = readByte()))
  					n = n * 10 + '0' - b;
  				return n;
  			} else if (!isNumber(b)) throw new NumberFormatException();
  			do
  				n = n * 10 + b - '0';
  			while (isNumber(b = readByte()));
  		} catch (java.util.NoSuchElementException e) {}
  		return n;
  	}
  
  	public double nextDouble() {
  		return Double.parseDouble(next());
  	}
  }
  
  class Arrays {
  
  	public static void sort(final int[] array) {
  		sort(array, 0, array.length);
  	}
  
  	public static void sort(final int[] array, int fromIndex, int toIndex) {
  		if (toIndex - fromIndex  <= 512) {
  			java.util.Arrays.sort(array, fromIndex, toIndex);
  			return;
  		}
  		sort(array, fromIndex, toIndex, 0, new int[array.length]);
  	}
  
  	private static final void sort(int[] a, final int from, final int to, final int l, final int[] bucket) {
  		if (to - from  <= 512) {
  			java.util.Arrays.sort(a, from, to);
  			return;
  		}
  		final int BUCKET_SIZE = 256;
  		final int INT_RECURSION = 4;
  		final int MASK = 0xff;
  		final int shift = l << 3;
  		final int[] cnt = new int[BUCKET_SIZE + 1];
  		final int[] put = new int[BUCKET_SIZE];
  		for (int i = from; i < to; i++) ++ cnt[(a[i] >>> shift & MASK) + 1];
  		for (int i = 0; i < BUCKET_SIZE; i++) cnt[i + 1] += cnt[i];
  		for (int i = from; i < to; i++) {
  			int bi = a[i] >>> shift & MASK;
  			bucket[cnt[bi] + put[bi]++] = a[i];
  		}
  		for (int i = BUCKET_SIZE - 1, idx = from; i >= 0; i--) {
  			int begin = cnt[i];
  			int len = cnt[i + 1] - begin;
  			System.arraycopy(bucket, begin, a, idx, len);
  			idx += len;
  	    }
  		final int nxtL = l + 1;
  		if (nxtL < INT_RECURSION) {
  			sort(a, from, to, nxtL, bucket);
  			if (l == 0) {
  				int lft, rgt;
  				lft = from - 1; rgt = to;
  				while (rgt - lft > 1) {
  					int mid = lft + rgt >> 1;
  					if (a[mid] < 0) lft = mid;
  					else rgt = mid;
  				}
  				reverse(a, from, rgt);
  				reverse(a, rgt, to);
  	        }
  	    }
  	}
  
  	public static void sort(final long[] array) {
  		sort(array, 0, array.length);
  	}
  
  	public static void sort(final long[] array, int fromIndex, int toIndex) {
  		if (toIndex - fromIndex  <= 512) {
  			java.util.Arrays.sort(array, fromIndex, toIndex);
  			return;
  		}
  		sort(array, fromIndex, toIndex, 0, new long[array.length]);
  	}
  
  	private static final void sort(long[] a, final int from, final int to, final int l, final long[] bucket) {
  		final int BUCKET_SIZE = 256;
  		final int LONG_RECURSION = 8;
  		final int MASK = 0xff;
  		final int shift = l << 3;
  		final int[] cnt = new int[BUCKET_SIZE + 1];
  		final int[] put = new int[BUCKET_SIZE];
  		for (int i = from; i < to; i++) ++ cnt[(int) ((a[i] >>> shift & MASK) + 1)];
  		for (int i = 0; i < BUCKET_SIZE; i++) cnt[i + 1] += cnt[i];
  		for (int i = from; i < to; i++) {
  			int bi = (int) (a[i] >>> shift & MASK);
  			bucket[cnt[bi] + put[bi]++] = a[i];
  		}
  		for (int i = BUCKET_SIZE - 1, idx = from; i >= 0; i--) {
  			int begin = cnt[i];
  			int len = cnt[i + 1] - begin;
  			System.arraycopy(bucket, begin, a, idx, len);
  			idx += len;
  	    }
  		final int nxtL = l + 1;
  		if (nxtL < LONG_RECURSION) {
  			sort(a, from, to, nxtL, bucket);
  			if (l == 0) {
  				int lft, rgt;
  				lft = from - 1; rgt = to;
  				while (rgt - lft > 1) {
  					int mid = lft + rgt >> 1;
  					if (a[mid] < 0) lft = mid;
  					else rgt = mid;
  				}
  				reverse(a, from, rgt);
  				reverse(a, rgt, to);
  	        }
  	    }
  	}
  
  	public static void reverse(int[] array) {
  		reverse(array, 0, array.length);
  	}
  
  	public static void reverse(int[] array, int fromIndex, int toIndex) {
  		for (-- toIndex;fromIndex < toIndex;++ fromIndex, -- toIndex) {
  			int swap = array[fromIndex];
  			array[fromIndex] = array[toIndex];
  			array[toIndex] = swap;
  		}
  	}
  
  	public static void reverse(long[] array) {
  		reverse(array, 0, array.length);
  	}
  
  	public static void reverse(long[] array, int fromIndex, int toIndex) {
  		for (-- toIndex;fromIndex < toIndex;++ fromIndex, -- toIndex) {
  			long swap = array[fromIndex];
  			array[fromIndex] = array[toIndex];
  			array[toIndex] = swap;
  		}
  	}
  
  	public static void shuffle(int[] array) {
  		java.util.Random rnd = new java.util.Random();
  		for (int i = 0;i < array.length;++ i) {
  			int j = rnd.nextInt(array.length - i) + i;
  			int swap = array[i];
  			array[i] = array[j];
  			array[j] = swap;
  		}
  	}
  
  	public static void shuffle(long[] array) {
  		java.util.Random rnd = new java.util.Random();
  		for (int i = 0;i < array.length;++ i) {
  			int j = rnd.nextInt(array.length - i) + i;
  			long swap = array[i];
  			array[i] = array[j];
  			array[j] = swap;
  		}
  	}
  }
  
  class IntMath {
  
  	public static int gcd(int a, int b) {
  		while (a != 0)
  			if ((b %= a) != 0) a %= b;
  			else return a;
  		return b;
  	}
  
  	public static int gcd(int... array) {
  		int ret = array[0];
  		for (int i = 1; i < array.length; ++i)
  			ret = gcd(ret, array[i]);
  		return ret;
  	}
  
  	public static long gcd(long a, long b) {
  		while (a != 0)
  			if ((b %= a) != 0) a %= b;
  			else return a;
  		return b;
  	}
  
  	public static long gcd(long... array) {
  		long ret = array[0];
  		for (int i = 1; i < array.length; ++i)
  			ret = gcd(ret, array[i]);
  		return ret;
  	}
  
  	public static long lcm(long a, long b) {
  		return a / gcd(a, b) * b;
  	}
  
  	public static int pow(int a, int b) {
  		int ans = 1;
  		for (int mul = a; b > 0; b >>= 1, mul *= mul)
  			if ((b & 1) != 0) ans *= mul;
  		return ans;
  	}
  
  	public static long pow(long a, long b) {
  		long ans = 1;
  		for (long mul = a; b > 0; b >>= 1, mul *= mul)
  			if ((b & 1) != 0) ans *= mul;
  		return ans;
  	}
  
  	public static int pow(int a, long b, int mod) {
  		if (b < 0) b = b % (mod - 1) + mod - 1;
  		long ans = 1;
  		for (long mul = a; b > 0; b >>= 1, mul = mul * mul % mod)
  			if ((b & 1) != 0) ans = ans * mul % mod;
  		return (int)ans;
  	}
  
  	public static int pow(long a, long b, int mod) {
  		return pow((int)(a % mod), b, mod);
  	}
  
  	public static int floorsqrt(long n) {
  		return (int)Math.sqrt(n + 0.1);
  	}
  
  	public static int ceilsqrt(long n) {
  		return n <= 1 ? (int)n : (int)Math.sqrt(n - 0.1) + 1;
  	}
  }
  