/*Bismillahir Rahmanir Rahim*///{
#include <bits/stdc++.h>
#include <ext/numeric>
using namespace std; using __gnu_cxx::power;
using ll = long long; using ull = unsigned long long; using ld = long double;
const ll llinf = (1ll<<61)-1; const double eps = 1e-6, ldeps = 1e-9;
struct Dbg { static constexpr auto &os = cout;   // replace by cerr in interactive.
template<class C> static auto dud(C *x)->decltype(os << *x, 0);
template<class C> static char dud(...);
template<class C> typename enable_if<sizeof dud<C>(0)!=1,Dbg&>::type operator<<(const C &x) {os<<x; return *this;}
template<class C> Dbg &dump(C b, C e) {
    for (struct{C i;int j;} i={(*this<<"\n[",b),0}; i.i!=e and i.j<26; i.i++, i.j++) *this<<", "+2*(i.i==b)<<*i.i;
    return *this << ']';
}
template<class C> typename enable_if<sizeof dud<C>(0)==1, Dbg&>::type operator<<(const C &x) {
    return dump(begin(x), end(x));
}
template<class C, size_t X> typename enable_if<!is_same<C, const char>::value, Dbg&>::type operator<<(C (&x)[X]) {
    return dump(begin(x), end(x));
}
template<class B, class C> Dbg &operator<<(const pair<B, C> &x) {return *this<<'{'<<x.first<<", "<<x.second<<'}';}
Dbg &operator<<(ostream&(*x)(std::ostream&)) { os << x; return *this; }
} dbg;
void err(istringstream *iss) { delete iss; }
template<class C, class... Args> void err(istringstream *iss, const C &val, const Args &... args) {
    string name; *iss >> name; if (name.back()==',') name.pop_back();
    dbg << name << " = " << val << "; ", err(iss, args...);
}
#define bug(args...) dbg << __LINE__ << ": ", err(new istringstream(#args), args), dbg << endl
#define cbug(a, args...) if (a) bug(args);
#define ASSERT(a, o, b, args...) if (!((a)o(b))) bug(a, b, ##args), assert((a)o(b));
#define sl(a) int(strlen(a))
#define sz(a) int(a.size())
int T, Q, cn;//}
const int inf = 998244353, mxn = 100005;

template<class C, class D> C& operator +=(C &x, const D &y) { return x = x+y; }//{
template<class C, class D> C& operator -=(C &x, const D &y) { return x = x-y; }
template<class C, class D> C& operator *=(C &x, const D &y) { return x = x*y; }
template<class C, class D> bool operator ==(const C &ls, const D &rs) { return !(ls<rs or rs<ls); }
template<class C, class D> bool operator !=(const C &ls, const D &rs) { return !(rs==ls); }
template<class C, class D> bool operator >(const C &ls, const D &rs) { return (rs<ls); }
template<class C, class D> bool operator <=(const C &ls, const D &rs) { return !(rs<ls); }
template<class C, class D> bool operator >=(const C &ls, const D &rs) { return !(ls<rs); }

struct Int// Make sure to not do any operation with non-modded(except *, which must be int, *1 to mod forcefully)
{
    int x;
    Int() = default;
    Int(const int &rs) : x(rs + (rs>=0 ? 0 : inf)) {};
    Int operator -() { return inf-*this; }
    // Int operator ~() = delete;
    Int operator ~() { return power(*this, inf-2); }
    Int operator +(const Int &rs) const { return x+rs.x>=inf ? x+rs.x-inf : x+rs.x; }
    Int operator -(const Int &rs) const { return x-rs.x<0 ? x-rs.x+inf : x-rs.x; }
    Int operator *(const Int &rs) const { return int(x*ll(rs.x)%inf); }
    Int operator <<(const int &rs) { return rs==1 ? *this+*this : *this*Int{1<<rs}; }
    Int& operator <<=(const int &rs) { return *this = *this<<rs; }
    Int& operator >>=(const int &rs) { return x>>=rs, *this; }  // only for power()
    Int& operator ++() { return *this += 1; }
    Int& operator --() { return *this -= 1; }
    Int operator ++(int) { Int ret = x; ++*this; return ret; }
    Int operator --(int) { Int ret = x; --*this; return ret; }
    friend istream& operator >>(istream &is, Int &rs) { return is>>rs.x; }
    friend ostream& operator <<(ostream &os, const Int &rs) { return os<<rs.x; }
    friend Int operator +(const Int &ls, const int &rs) { return ls+Int(rs); }
    friend Int operator +(const int &ls, const Int &rs) { return Int(ls)+rs; }
    friend Int operator -(const Int &ls, const int &rs) { return ls-Int(rs); }
    friend Int operator -(const int &ls, const Int &rs) { return Int(ls)-rs; }
    friend Int operator *(const Int &ls, const int &rs) { return ls*Int(rs); }
    friend Int operator *(const int &ls, const Int &rs) { return Int(ls)*rs; }
    bool operator <(const Int &rs) const { return x<rs.x; }
    friend bool operator <(const int &ls, const Int &rs) { return ls<rs.x; }
    friend bool operator <(const Int &ls, const int &rs) { return ls.x<rs; }
};

Int operator""_i(unsigned long long x) { return {int(x)}; }//}

int n, m[130];
char s[mxn*3], mark[mxn*3];
priority_queue<int, vector<int>, greater<int> > pq[3];
deque<int> dq[3];
bitset<mxn*3> vstd;

signed main() { cin.tie(0)->sync_with_stdio(0); cin.exceptions(cin.failbit); cout.precision(11);
/*
It's easy to find the min answer. When building the min answer, some elements are subtracted, some are added.
Then, we can do whatever we want to do just keeping the addition and subtraction same: I was stuck in this part, seen it:(.
*/
    m['R'] = 0, m['G'] = 1, m['B'] = 2;
    cin >> n >> s;
    for (int i = 0; i < 3*n; i++) {
        pq[m[s[i]]].push(i);
    }

    for (int i = 0; i < 3*n; i++) {
        if (vstd[i]) continue;
        int mx = 0;
        for (int j = 0; j < 3; j++) {
            mx = max(mx, pq[j].top()); vstd[pq[j].top()] = 1, mark[pq[j].top()] = '.', pq[j].pop();
        }
        mark[i] = '-', mark[mx] = '+';
    }

    m['-'] = 0, m['.'] = 1, m['+'] = 2;
    Int ans = 1, unmatchedMinus = 0, unmatchedMinusDot = 0;
    for (int i = 0; i < 3*n; i++) {
        if (mark[i]=='-') {
            ++unmatchedMinus;
        } else if (mark[i]=='.') {
            ans *= unmatchedMinus--, ++unmatchedMinusDot;
        } else {
            ans *= unmatchedMinusDot--;
        }
    }
    for (int i = 2; i <= n; i++) {
        ans *= i;
    }
    cout << ans << '\n';
}

Measured memory_bytes: 2288