#include<bits/stdc++.h>
using namespace std;

template <int MOD_> struct modnum {
	static constexpr int MOD = MOD_;
	static_assert(MOD_ > 0, "MOD must be positive");

private:
	using ll = long long;

	int v;

	static int minv(int a, int m) {
		a %= m;
		assert(a);
		return a == 1 ? 1 : int(m - ll(minv(m, a)) * ll(m) / a);
	}

public:

	modnum() : v(0) {}
	modnum(ll v_) : v(int(v_ % MOD)) { if (v < 0) v += MOD; }
	explicit operator int() const { return v; }
	friend std::ostream& operator << (std::ostream& out, const modnum& n) { return out << int(n); }
	friend std::istream& operator >> (std::istream& in, modnum& n) { ll v_; in >> v_; n = modnum(v_); return in; }

	friend bool operator == (const modnum& a, const modnum& b) { return a.v == b.v; }
	friend bool operator != (const modnum& a, const modnum& b) { return a.v != b.v; }

	modnum inv() const {
		modnum res;
		res.v = minv(v, MOD);
		return res;
	}
	modnum neg() const {
		modnum res;
		res.v = v ? MOD-v : 0;
		return res;
	}

	modnum operator- () const {
		return neg();
	}
	modnum operator+ () const {
		return modnum(*this);
	}

	modnum& operator ++ () {
		v ++;
		if (v == MOD) v = 0;
		return *this;
	}
	modnum& operator -- () {
		if (v == 0) v = MOD;
		v --;
		return *this;
	}
	modnum& operator += (const modnum& o) {
		v += o.v;
		if (v >= MOD) v -= MOD;
		return *this;
	}
	modnum& operator -= (const modnum& o) {
		v -= o.v;
		if (v < 0) v += MOD;
		return *this;
	}
	modnum& operator *= (const modnum& o) {
		v = int(ll(v) * ll(o.v) % MOD);
		return *this;
	}
	modnum& operator /= (const modnum& o) {
		return *this *= o.inv();
	}

	friend modnum operator ++ (modnum& a, int) { modnum r = a; ++a; return r; }
	friend modnum operator -- (modnum& a, int) { modnum r = a; --a; return r; }
	friend modnum operator + (const modnum& a, const modnum& b) { return modnum(a) += b; }
	friend modnum operator - (const modnum& a, const modnum& b) { return modnum(a) -= b; }
	friend modnum operator * (const modnum& a, const modnum& b) { return modnum(a) *= b; }
	friend modnum operator / (const modnum& a, const modnum& b) { return modnum(a) /= b; }
};

using num = modnum<998244353>;

const int MAXN = 1.1e5;
int N;
char S[MAXN * 3];
int V[MAXN * 3];

vector<int> pos[3];

vector<int> probs[2][3];

int main() {
	ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
	cin >> N;
	cin >> S;
	for (int i = 0; i < 3 * N; i++) {
		char c = S[i];
		if (c == 'R') V[i] = 0;
		else if (c == 'G') V[i] = 1;
		else if (c == 'B') V[i] = 2;
		else assert(false);
	}

	for (int i = 0; i < 3 * N; i++) {
		pos[V[i]].push_back(i);
	}

	assert(int(pos[0].size()) == N);
	assert(int(pos[1].size()) == N);
	assert(int(pos[2].size()) == N);

	for (int i = 0; i < N; i++) {
		vector<int> locs({pos[0][i], pos[1][i], pos[2][i]});
		sort(locs.begin(), locs.end());
		probs[0][V[locs[0]]].push_back(locs[0]);
		probs[0][V[locs[0]]].push_back(locs[1]);

		probs[1][V[locs[2]]].push_back(locs[1]);
		probs[1][V[locs[2]]].push_back(locs[2]);
	}

	num ans = 1;
	for (int i = 1; i <= N; i++) ans *= i;

	for (int z = 0; z < 2; z++) {
		for (int a = 0; a < 3; a++) {
			sort(probs[z][a].begin(), probs[z][a].end());
			int nLo = 0;
			for (int i : probs[z][a]) {
				if ((V[i] == a) == (z == 0)) {
					nLo ++;
				} else {
					assert(nLo > 0);
					ans *= nLo;
					nLo --;
				}
			}
		}
	}
	cout << ans << '\n';

	return 0;
}


Measured memory_bytes: 5936