#include <bits/stdc++.h>
// #include <atcoder/all>
using namespace std;
// using namespace atcoder;
template <class T, class U>
ostream &operator<<(ostream &os, const pair<T, U> &p) {
  os << "(" << p.first << "," << p.second << ")";
  return os;
}
#ifdef __LOCAL
#define debug(x) cerr << __LINE__ << ": " << #x << " = " << (x) << '\n'
#define debugArray(x, n)                                      \
  cerr << __LINE__ << ": " << #x << " = {";                   \
  for (long long hoge = 0; (hoge) < (long long)(n); ++(hoge)) \
    cerr << ((hoge) ? "," : "") << x[hoge];                   \
  cerr << "}" << '\n'
#define debugMatrix(x, h, w)                                         \
  cerr << __LINE__ << ": " << #x << " =\n";                          \
  for (long long hoge = 0; (hoge) < (long long)(h); ++(hoge)) {      \
    cerr << ((hoge ? " {" : "{{"));                                  \
    for (long long fuga = 0; (fuga) < (long long)(w); ++(fuga))      \
      cerr << ((fuga ? ", " : "")) << x[hoge][fuga];                 \
    cerr << "}" << (hoge + 1 == (long long)(h) ? "}" : ",") << '\n'; \
  }
#else
#define debug(x) (void(0))
#define debugArray(x, n) (void(0))
#define debugMatrix(x, h, w) (void(0))
#endif

template <int mod>
struct ModInt {
  int64_t x;
  ModInt() : x(0) {}
  ModInt(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod)) {}
  ModInt &operator+=(const ModInt &p) {
    if ((x += p.x) >= mod) x -= mod;
    return *this;
  }
  ModInt &operator-=(const ModInt &p) {
    if ((x += mod - p.x) >= mod) x -= mod;
    return *this;
  }
  ModInt &operator*=(const ModInt &p) {
    x = (int)(1LL * x * p.x % mod);
    return *this;
  }
  ModInt &operator/=(const ModInt &p) { return *this *= p.inverse(); }
  ModInt operator-() const { return ModInt() - *this; }
  ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; }
  ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; }
  ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; }
  ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; }
  bool operator==(const ModInt &p) const { return x == p.x; }
  bool operator!=(const ModInt &p) const { return x != p.x; }
  ModInt inverse() const {
    int a = x, b = mod, u = 1, v = 0, t;
    while (b) t = a / b, swap(a -= t * b, b), swap(u -= t * v, v);
    return ModInt(u);
  }
  ModInt pow(int64_t e) const {
    ModInt ret(1);
    for (ModInt b = *this; e; e >>= 1, b *= b)
      if (e & 1) ret *= b;
    return ret;
  }
  friend ostream &operator<<(ostream &os, const ModInt &p) { return os << p.x; }
  friend istream &operator>>(istream &is, ModInt &a) {
    int64_t t;
    is >> t;
    a = ModInt<mod>(t);
    return (is);
  }
  static int modulo() { return mod; }
  int get() const { return x; }
};

signed main() {
  cin.tie(0);
  ios::sync_with_stdio(0);
  using Mint = ModInt<998244353>;
  int N;
  cin >> N;
  string S;
  cin >> S;
  int kind[3 * N];
  int r = 0, g = 0, b = 0;
  for (int i = 0; i < 3 * N; i++) {
    if (S[i] == 'R') {
      kind[i] = r++;
    } else if (S[i] == 'G') {
      kind[i] = g++;
    } else {
      kind[i] = b++;
    }
  }
  debugArray(kind, N * 3);
  int a[N][3];
  int idx[N];
  fill(idx, idx + N, 0);
  for (int i = 0; i < 3 * N; i++) {
    a[kind[i]][idx[kind[i]]++] = i;
  }
  Mint ans = 1;
  int cnt1 = 0, cnt2 = 0;
  int j = 0, k = 0;
  for (int i = 0; i < N; i++) {
    while (j < N && a[j][0] < a[i][1]) cnt1++, j++;
    while (k < N && a[k][1] < a[i][2]) cnt2++, k++;
    ans *= cnt1--;
    ans *= cnt2--;
  }
  for (int i = 1; i <= N; i++) ans *= i;
  cout << ans << '\n';
  return 0;
}


Measured memory_bytes: 6464