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: 
  import java.io.BufferedReader;
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.FileNotFoundException;
  import java.io.FileOutputStream;
  import java.io.InputStreamReader;
  import java.io.PrintWriter;
  import java.math.BigInteger;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.BitSet;
  import java.util.Calendar;
  import java.util.Collections;
  import java.util.Comparator;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.LinkedList;
  import java.util.PriorityQueue;
  import java.util.SortedSet;
  import java.util.Stack;
  import java.util.StringTokenizer;
  import java.util.TreeMap;
  import java.util.TreeSet;
  
  /**
   * #
   *
   * @author pttrung
   */
  public class C_Round_747_Div2 {
      public static int MOD = 998244353;
  
      static double[][][] dp;
  
  
      public static void main(String[] args) throws FileNotFoundException {
          // PrintWriter out = new PrintWriter(new FileOutputStream(new File(
          // "output.txt")));
          PrintWriter out = new PrintWriter(System.out);
          Scanner in = new Scanner();
          int T = in.nextInt();
          for (int z = 0; z < T; z++) {
              int n = in.nextInt();
              char c = in.next().charAt(0);
              String data = in.next();
  //            if (z == 70) {
  //                System.out.println(n + " " + c + " " + data);
  //            }
              boolean[] check = new boolean[n + 1];
              int total = 0;
              int max = 0;
              int other = n;
              for (int i = 0; i < n; i++) {
                  if (data.charAt(i) != c) {
                      check[i + 1] = true;
                      max = i + 1;
                      total++;
                      continue;
                  }
                  other = i + 1;
              }
              if (total == 0) {
                  out.println(0);
              } else if (max < n) {
                  out.println(1);
                  out.println(n);
              } else {
                  boolean ok = true;
                  for (int i = 1; i < check.length; i++) {
                      if (!check[i]) {
                          continue;
                      }
                      ok &= i % other != 0;
                  }
                  if (ok) {
                      out.println(1);
                      out.println(other);
                  }
                  boolean[] p = new boolean[n + 1];
  
                  int o = -1;
                  for (int i = 2; i < p.length && !ok; i++) {
                      if (p[i]) {
                          continue;
                      }
                      ok = true;
                      for (int j = i; j < p.length; j += i) {
                          ok &= !check[j];
                          p[j] = true;
                      }
                      if (ok) {
                          out.println(1);
                          out.println(i);
                          break;
                      }
                      if (n % i != 0) {
                          o = i;
                      }
                  }
                  if (!ok) {
                      out.println(2);
                      out.println(n + " " + o);
                  }
              }
          }
          out.close();
      }
  
  
      static int abs(int a) {
          return a < 0 ? -a : a;
      }
  
  
      public static int[] KMP(String val) {
          int i = 0;
          int j = -1;
          int[] result = new int[val.length() + 1];
          result[0] = -1;
          while (i < val.length()) {
              while (j >= 0 && val.charAt(j) != val.charAt(i)) {
                  j = result[j];
              }
              j++;
              i++;
              result[i] = j;
          }
          return result;
  
      }
  
      public static boolean nextPer(int[] data) {
          int i = data.length - 1;
          while (i > 0 && data[i] < data[i - 1]) {
              i--;
          }
          if (i == 0) {
              return false;
          }
          int j = data.length - 1;
          while (data[j] < data[i - 1]) {
              j--;
          }
          int temp = data[i - 1];
          data[i - 1] = data[j];
          data[j] = temp;
          Arrays.sort(data, i, data.length);
          return true;
      }
  
      public static int digit(long n) {
          int result = 0;
          while (n > 0) {
              n /= 10;
              result++;
          }
          return result;
      }
  
      public static double dist(long a, long b, long x, long y) {
          double val = (b - a) * (b - a) + (x - y) * (x - y);
          val = Math.sqrt(val);
          double other = x * x + a * a;
          other = Math.sqrt(other);
          return val + other;
  
      }
  
      public static class Point {
  
          int x;
          int y;
  
          public Point(int start, int end) {
              this.x = start;
              this.y = end;
          }
  
          public String toString() {
              return x + " " + y;
          }
  
      }
  
      public static class FT {
  
          long[] data;
  
          FT(int n) {
              data = new long[n];
          }
  
          public void update(int index, long value) {
              while (index < data.length) {
                  data[index] += value;
                  index += (index & (-index));
              }
          }
  
          public long get(int index) {
  
              long result = 0;
              while (index > 0) {
                  result += data[index];
                  index -= (index & (-index));
              }
              return result;
  
          }
      }
  
      public static long gcd(long a, long b) {
          if (b == 0) {
              return a;
          }
          return gcd(b, a % b);
      }
  
      public static long pow(long a, int b) {
          if (b == 0) {
              return 1;
          }
          if (b == 1) {
              return a;
          }
  
          long val = pow(a, b / 2);
          if (b % 2 == 0) {
              return (val * val);
          } else {
              return (val * ((val * a)));
  
          }
      }
  
      static class Scanner {
  
          BufferedReader br;
          StringTokenizer st;
  
          public Scanner() throws FileNotFoundException {
              // System.setOut(new PrintStream(new BufferedOutputStream(System.out), true));
              br = new BufferedReader(new InputStreamReader(System.in));
              //br = new BufferedReader(new InputStreamReader(new FileInputStream(new File("input.txt"))));
          }
  
          public String next() {
  
              while (st == null || !st.hasMoreTokens()) {
                  try {
                      st = new StringTokenizer(br.readLine());
                  } catch (Exception e) {
                      throw new RuntimeException();
                  }
              }
              return st.nextToken();
          }
  
          public long nextLong() {
              return Long.parseLong(next());
          }
  
          public int nextInt() {
              return Integer.parseInt(next());
          }
  
          public double nextDouble() {
              return Double.parseDouble(next());
          }
  
          public String nextLine() {
              st = null;
              try {
                  return br.readLine();
              } catch (Exception e) {
                  throw new RuntimeException();
              }
          }
  
          public boolean endLine() {
              try {
                  String next = br.readLine();
                  while (next != null && next.trim().isEmpty()) {
                      next = br.readLine();
                  }
                  if (next == null) {
                      return true;
                  }
                  st = new StringTokenizer(next);
                  return st.hasMoreTokens();
              } catch (Exception e) {
                  throw new RuntimeException();
              }
          }
      }
  }