public class Main {

  private static void solve() {
    int n = ni();
    char[] s = ns();

    // {G or B, R or B, G or R}
    long[] cnt1 = new long[3];
    // {R, G, B}
    long[] cnt2 = new long[3];
    long ret = 1;
    int mod = 998244353;
    for (int i = 0; i < n * 3; i++) {
      char c = s[i];
      int x;
      if (c == 'R') {
        x = 0;
      } else if (c == 'G') {
        x = 1;
      } else {
        x = 2;
      }

      if (cnt2[x] > 0) {
        ret *= cnt2[x];
        ret %= mod;
        cnt2[x]--;
      } else if (x == 0 && cnt1[1] > 0) {
        ret *= cnt1[1];
        ret %= mod;
        cnt1[1]--;
        cnt2[2]++;
      } else if (x == 0 && cnt1[2] > 0) {
        ret *= cnt1[2];
        ret %= mod;
        cnt1[2]--;
        cnt2[1]++;
      } else if (x == 1 && cnt1[0] > 0) {
        ret *= cnt1[0];
        ret %= mod;
        cnt1[0]--;
        cnt2[2]++;
      } else if (x == 1 && cnt1[2] > 0) {
        ret *= cnt1[2];
        ret %= mod;
        cnt1[2]--;
        cnt2[0]++;
      } else if (x == 2 && cnt1[0] > 0) {
        ret *= cnt1[0];
        ret %= mod;
        cnt1[0]--;
        cnt2[1]++;
      } else if (x == 2 && cnt1[1] > 0) {
        ret *= cnt1[1];
        ret %= mod;
        cnt1[1]--;
        cnt2[0]++;
      } else {
        cnt1[x]++;
      }
    }
    for (int i = 0; i < n; i++) {
      ret *= i + 1;
      ret %= mod;
    }
    System.out.println(ret);
  }

  public static void main(String[] args) {
    new Thread(null, new Runnable() {
      @Override
      public void run() {
        long start = System.currentTimeMillis();
        String debug = args.length > 0 ? args[0] : null;
        if (debug != null) {
          try {
            is = java.nio.file.Files.newInputStream(java.nio.file.Paths.get(debug));
          } catch (Exception e) {
            throw new RuntimeException(e);
          }
        }
        reader = new java.io.BufferedReader(new java.io.InputStreamReader(is), 32768);
        solve();
        out.flush();
        tr((System.currentTimeMillis() - start) + "ms");
      }
    }, "", 64000000).start();
  }

  private static java.io.InputStream is = System.in;
  private static java.io.PrintWriter out = new java.io.PrintWriter(System.out);
  private static java.util.StringTokenizer tokenizer = null;
  private static java.io.BufferedReader reader;

  public static String next() {
    while (tokenizer == null || !tokenizer.hasMoreTokens()) {
      try {
        tokenizer = new java.util.StringTokenizer(reader.readLine());
      } catch (Exception e) {
        throw new RuntimeException(e);
      }
    }
    return tokenizer.nextToken();
  }

  private static double nd() {
    return Double.parseDouble(next());
  }

  private static long nl() {
    return Long.parseLong(next());
  }

  private static int[] na(int n) {
    int[] a = new int[n];
    for (int i = 0; i < n; i++)
      a[i] = ni();
    return a;
  }

  private static char[] ns() {
    return next().toCharArray();
  }

  private static long[] nal(int n) {
    long[] a = new long[n];
    for (int i = 0; i < n; i++)
      a[i] = nl();
    return a;
  }

  private static int[][] ntable(int n, int m) {
    int[][] table = new int[n][m];
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < m; j++) {
        table[i][j] = ni();
      }
    }
    return table;
  }

  private static int[][] nlist(int n, int m) {
    int[][] table = new int[m][n];
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < m; j++) {
        table[j][i] = ni();
      }
    }
    return table;
  }

  private static int ni() {
    return Integer.parseInt(next());
  }

  private static void tr(Object... o) {
    if (is != System.in)
      System.out.println(java.util.Arrays.deepToString(o));
  }
}



Measured memory_bytes: 28504