#include <bits/stdc++.h>
#define int long long
#define ll long long
using ull = unsigned long long;
using namespace std;
const int INF = 1ll << 50;
const int MOD = 998244353;
#define dump(x)                             \
    if (dbg) {                              \
        cerr << #x << " = " << (x) << endl; \
    }
#define overload4(_1, _2, _3, _4, name, ...) name
#define FOR1(n) for (ll i = 0; i < (n); ++i)
#define FOR2(i, n) for (ll i = 0; i < (n); ++i)
#define FOR3(i, a, b) for (ll i = (a); i < (b); ++i)
#define FOR4(i, a, b, c) for (ll i = (a); i < (b); i += (c))
#define FOR(...) overload4(__VA_ARGS__, FOR4, FOR3, FOR2, FOR1)(__VA_ARGS__)
#define FORR(i, a, b) for (int i = (a); i <= (b); ++i)
#define bit(n, k) ((n >> k) & 1) /*nのk bit目*/
template <class T>
bool chmin(T& a, const T& b) {
    if (a > b) {
        a = b;
        return 1;
    } else
        return 0;
}
template <class T>
bool chmax(T& a, const T& b) {
    if (a < b) {
        a = b;
        return 1;
    } else
        return 0;
}
void Yes(bool flag = true) {
    if (flag)
        cout << "Yes" << endl;
    else
        cout << "No" << endl;
}
void No(bool flag = true) {
    Yes(!flag);
}
void YES(bool flag = true) {
    if (flag)
        cout << "YES" << endl;
    else
        cout << "NO" << endl;
}
void NO(bool flag = true) {
    YES(!flag);
}
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define all(v) (v).begin(), (v).end()
#define SZ(x) ((int)(x).size())
#define vi vector<int>
//#define P pair<int, int>
//#define V vector<int>
//#define S set<int>
#define itn int
bool dbg = false;
//Template by yosupo
template <uint MD>
struct ModInt {
    using M = ModInt;
    const static M G;
    uint v;
    ModInt(ll _v = 0) { set_v(_v % MD + MD); }
    M& set_v(uint _v) {
        v = (_v < MD) ? _v : _v - MD;
        return *this;
    }
    explicit operator bool() const { return v != 0; }
    M operator-() const { return M() - *this; }
    M operator+(const M& r) const { return M().set_v(v + r.v); }
    M operator-(const M& r) const { return M().set_v(v + MD - r.v); }
    M operator*(const M& r) const { return M().set_v(ull(v) * r.v % MD); }
    M operator/(const M& r) const { return *this * r.inv(); }
    M& operator+=(const M& r) { return *this = *this + r; }
    M& operator-=(const M& r) { return *this = *this - r; }
    M& operator*=(const M& r) { return *this = *this * r; }
    M& operator/=(const M& r) { return *this = *this / r; }
    bool operator==(const M& r) const { return v == r.v; }
    M pow(ll n) const {
        M x = *this, r = 1;
        while (n) {
            if (n & 1)
                r *= x;
            x *= x;
            n >>= 1;
        }
        return r;
    }
    M inv() const { return pow(MD - 2); }
    friend ostream& operator<<(ostream& os, const M& r) { return os << r.v; }
};
using Mint = ModInt<MOD>;

int N;
string S;
vector<int> X[4];
vector<int> A, B, C;
vector<int> L, R;
int F[303030];


void solve() {
    for (int i = 0; i < S.size(); i++) {
        X[S[i]].pb(i);
    }
    FOR(N) {
        int MIN = min({X[0][i], X[1][i], X[2][i]});
        int MAX = max({X[0][i], X[1][i], X[2][i]});
        A.pb(MIN);
        C.pb(MAX);
        B.pb(X[0][i] + X[1][i] + X[2][i] - MIN - MAX);
        int l = INF, r = 0;
        FOR(c, 3) {
            chmin(l, X[c][i]);
            chmax(r, X[c][i]);
        }
        L.pb(S[l]);
        R.pb(S[r]);
    }
    FOR(N) {
        F[A[i]] = 0;
        F[B[i]] = 1;
        F[C[i]] = 2;
    }
    Mint ans = 1;
    int cnt[5] = {};
    int now = 0;
    FOR(N * 3) {
        //cerr << i << " : " << L[i] << endl;
        if (F[i] == 0) {
            cnt[S[i]]++;
        } else if (F[i] == 1) {
            ans *= cnt[L[now]];
            cnt[L[now]]--;
            //cout << i << " : " << now << " " << ans << endl;
            now++;
        }
    }
    cnt[0] = 0;
    cnt[1] = 0;
    cnt[2] = 0;
    now = N - 1;
    for (int i = N * 3 - 1; i >= 0; i--) {
        if (F[i] == 2) {
            cnt[S[i]]++;
        } else if (F[i] == 1) {
            ans *= cnt[R[now]];
            cnt[R[now]]--;
            now--;
        }
    }
    FOR(i, 1, N + 1)
    ans *= i;
    cout << ans << endl;
}

signed main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cin >> N;
    cin >> S;
    for (auto& c : S) {
        if (c == 'R')
            c = 0;
        else if (c == 'G')
            c = 1;
        else
            c = 2;
    }


    solve();
    return 0;
}


Measured memory_bytes: 10764