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

#define fs first
#define sc second

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }


// std::vector Declaration
template<typename T>
vector<T> make_v(size_t a) { return vector<T>(a); }
template<typename T,typename... Ts>
auto make_v(size_t a,Ts... ts) {
    return vector<decltype(make_v<T>(ts...))>(a,make_v<T>(ts...));
}

// std::vector Initialization
template<typename T>
void fill_all(T& arr, const T& v) { arr = v; }
template<typename T, typename U>
void fill_all(T& arr, const U& v) { for (auto& i : arr) fill_all(i, v); }

// std::vector Debug
template<typename T>
ostream& operator<<(ostream& os, const vector<T>& v) {
    os << "[";
    bool a = 1;
    for (auto e : v) {
        os << (a ? "" : " ");
        os << e;
        a = 0;
    }
    os << "]";
    return os;
}

// std::deque Debug
template<typename T>
ostream& operator<<(ostream& os, const deque<T>& d) {
    os << "[";
    bool a = 1;
    for (auto e : d) {
        os << (a ? "" : " ");
        os << e;
        a = 0;
    }
    os << "]";
    return os;
}

// std::pair Debug
template<typename T, typename U>
ostream& operator<<(ostream& os, const pair<T, U>& p) {
    os << "(" << p.first << " " << p.second << ")";
    return os;
}

// std::set Debug
template<typename T>
ostream& operator<<(ostream& os, const set<T>& st) {
    os << "{";
    bool a = 1;
    for (auto e : st) {
        os << (a ? "" : " ");
        os << e;
        a = 0;
    }
    os << "}";
    return os;
}

// std::multiset Debug
template<typename T>
ostream& operator<<(ostream& os, const multiset<T>& st) {
    os << "{";
    bool a = 1;
    for (auto e : st) {
        os << (a ? "" : " ");
        os << e;
        a = 0;
    }
    os << "}";
    return os;
}

// std::map Debug
template<typename T, typename U>
ostream& operator<<(ostream& os, const map<T, U>& mp) {
    os << "{";
    bool a = 1;
    for (auto e : mp) {
        os << (a ? "" : " ");
        os << e.first << ":" << e.second;
        a = 0;
    }
    os << "}";
    return os;
}

// std::tuple Debug
template<int N, class Tuple>
void out(ostream& os, const Tuple& t){}
template<int N, class Tuple, class H, class ...Ts>
void out(ostream& os, const Tuple& t) {
    if (N) os << " ";
    os << get<N>(t);
    out<N+1,Tuple,Ts...>(os, t);
}
template<class ...Ts>
ostream& operator<<(ostream& os, const tuple<Ts...>& t) {
    os << "(";
    out<0,tuple<Ts...>,Ts...>(os, t);
    os << ")";
    return os;
}

// Debug
#define DUMP(x) cerr<<#x<<" = "<<(x)<<endl


struct edge { int to, cost; };
ostream& operator<<(ostream& os, const edge& e) {
    os << "(" << e.to << ", " << e.cost << ")";
    return os;
}

const LL LINF = 1LL<<60;
const int IINF = 1<<30;
const LL MOD = 998244353;

template<long long mod>
struct modint {
    using LL = long long;

    LL val;
    modint(LL val=0) : val(((val % mod) + mod) % mod) {}

    const modint operator+() const { return *this; }
    const modint operator-() const { return (-val + mod) % mod; }
    const modint reciprocal() const { return power(mod-2); }

    modint& operator+=(const modint& rhs) { (val += rhs.val) %= mod; return *this; }
    modint& operator-=(const modint& rhs) { return *this += -rhs; }
    modint& operator*=(const modint& rhs) { (val *= rhs.val) %= mod; return *this; }
    modint& operator/=(const modint& rhs) { return *this *= rhs.reciprocal(); }

    const modint operator+(const modint& rhs) const { return modint(*this) += rhs; }
    const modint operator-(const modint& rhs) const { return modint(*this) -= rhs; }
    const modint operator*(const modint& rhs) const { return modint(*this) *= rhs; }
    const modint operator/(const modint& rhs) const { return modint(*this) /= rhs; }

    const modint power(long long n) const {
        modint ret = 1, tmp = val;
        while (n > 0) {
            if (n & 1) ret *= tmp;
            tmp *= tmp; n >>= 1;
        }
        return ret;
    }

    bool operator==(const modint& rhs) const { return val == rhs.val; }
    bool operator!=(const modint& rhs) const { return !(*this == rhs); }

    friend const modint operator+(const LL& lhs, const modint& rhs) {
        return modint(lhs) + rhs;
    }
    friend const modint operator-(const LL& lhs, const modint& rhs) {
        return modint(lhs) - rhs;
    }
    friend const modint operator*(const LL& lhs, const modint& rhs) {
        return modint(lhs) * rhs;
    }
    friend const modint operator/(const LL& lhs, const modint& rhs) {
        return modint(lhs) / rhs;
    }

    friend bool operator==(const LL& lhs, const modint& rhs) {
        return modint(lhs) == rhs;
    }
    friend bool operator!=(const LL& lhs, const modint& rhs) {
        return modint(lhs) != rhs;
    }

    friend ostream& operator<<(ostream& os, const modint& a) { return os << a.val; }
    friend istream& operator>>(istream& is, modint& a) {
        LL tmp; is >> tmp;
        a = tmp;
        return is;
    }
};

using GF = modint<998244353>;

int main()
{
    int n; cin >> n;
    string s; cin >> s;

    vector<int> R, G, B;
    for (int i = 0; i < 3*n; ++i) {
        if (s[i] == 'R') R.push_back(i);
        if (s[i] == 'G') G.push_back(i);
        if (s[i] == 'B') B.push_back(i);
    }

    vector<int> low, mid, high;
    for (int i = 0; i < n; ++i)
    {
        vector<int> tmp{ R[i], G[i], B[i] };
        sort(tmp.begin(), tmp.end());
        low.push_back(tmp[0]);
        mid.push_back(tmp[1]);
        high.push_back(tmp[2]);
    }

    GF ans = 1;

    {
        int j = 0;
        for (int i = 0; i < n; ++i) {
            while (j < n && low[j] < mid[i]) {
                ++j;
            }
            ans *= j - i;
        }
    }
    {
        int j = 0;
        for (int i = 0; i < n; ++i) {
            while (j < n && high[n-1-j] > mid[n-1-i]) {
                ++j;
            }
            ans *= j - i;
        }
    }

    for (int i = 1; i <= n; ++i) {
        ans *= i;
    }

    cout << ans << endl;

    return 0;
}


Measured memory_bytes: 3580