import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.complex, std.container, std.math, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }
real readReal() { return readToken.to!real; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }


struct ModInt(long M) {
  long x;
  this(in ModInt a) { x = a.x; }
  this(in long a) { x = a % M; if (x < 0) x += M; }
  ref ModInt opAssign(in long a) { return this = ModInt(a); }
  ref ModInt opOpAssign(string op)(in ModInt a) {
    static if (op == "+") { x += a.x; if (x >= M) x -= M; }
    else static if (op == "-") { x -= a.x; if (x < 0) x += M; }
    else static if (op == "*") { x *= a.x; x %= M; }
    else static assert(false);
    return this;
  }
  ref ModInt opOpAssign(string op)(in long a) { return mixin("this " ~ op ~ "= ModInt(a)"); }
  ModInt opUnary(string op)() const if (op == "-") { return ModInt(-x); }
  ModInt opBinary(string op, T)(in T a) const { return mixin("ModInt(this) " ~ op ~ "= a"); }
  ModInt opBinaryRight(string op)(in long a) const { return mixin("ModInt(a) " ~ op ~ "= this"); }
  string toString() const { return x.to!string; }
}

enum long MO = 998244353;
alias Mint = ModInt!MO;

int N;
string S;

void main() {
  try {
    for (; ; ) {
      N = readInt;
      S = readToken();
      
      auto A = new int[3 * N];
      foreach (i; 0 .. 3 * N) {
        A[i] = "RGB".indexOf(S[i]);
      }
      
      auto xss = new int[][3];
      foreach (i; 0 .. 3 * N) {
        xss[A[i]] ~= i;
      }
      debug {
        writeln("xss = ", xss);
      }
      
      auto yss = new int[][](N, 3);
      foreach (j; 0 .. N) {
        foreach (k; 0 .. 3) {
          yss[j][k] = xss[k][j];
        }
        sort(yss[j]);
      }
      debug {
        writeln("yss = ", yss);
      }
      
      auto zss = new int[][](3, N);
      foreach (k; 0 .. 3) {
        foreach (j; 0 .. N) {
          zss[k][j] = yss[j][k];
        }
        sort(zss[k]);
      }
      debug {
        writeln("zss = ", zss);
      }
      
      auto as = new int[][](3 * N, 3);
      foreach (i; 0 .. 3 * N) {
        as[i][] = -1;
      }
      foreach (j; 0 .. N) {
        foreach (k; 0 .. 3) {
          as[yss[j][1]][k] = A[yss[j][k]];
        }
      }
      
      Mint ans = 1;
      {
        auto cnt = new long[3];
        for (int j0 = 0, j1 = 0; j1 < N; ++j1) {
          for (; j0 < N && zss[0][j0] < zss[1][j1]; ++j0) {
            ++cnt[A[zss[0][j0]]];
          }
          debug {
            writeln(j1, " ", j0, " ", cnt);
          }
          const a = as[zss[1][j1]][0];
          ans *= cnt[a];
          --cnt[a];
        }
      }
      {
        auto cnt = new long[3];
        for (int j2 = N - 1, j1 = N - 1; j1 >= 0; --j1) {
          for (; j2 >= 0 && zss[2][j2] > zss[1][j1]; --j2) {
            ++cnt[A[zss[2][j2]]];
          }
          debug {
            writeln(j1, " ", j2, " ", cnt);
          }
          const a = as[zss[1][j1]][2];
          ans *= cnt[a];
          --cnt[a];
        }
      }
      foreach (h; 1 .. N + 1) {
        ans *= h;
      }
      writeln(ans);
    }
  } catch (EOFException e) {
  }
}
