#include <bits/stdc++.h>
#define whlie while
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define rep(i,N) for(int i = 0; i < (N); i++)
#define repr(i,N) for(auto i = (N) - 1; i >= 0; i -= 1)
#define each(x,v) for(auto& x : v)
#define all(v) (v).begin(),(v).end()
#define sz(v) ((int)(v).size())
#define vrep(v,it) for(auto it = v.begin(); it != v.end(); it++)
#define vrepr(v,it) for(auto it = v.rbegin(); it != v.rend(); it++)
#define ini(...) int __VA_ARGS__; in(__VA_ARGS__)
#define inl(...) ll __VA_ARGS__; in(__VA_ARGS__)
#define ins(...) string __VA_ARGS__; in(__VA_ARGS__)
#define rand mtrand
#ifdef NyaanDebug
  #include "NyaanDebug.h"
  #define trc(...) do { cout << #__VA_ARGS__ << " = "; dbg_out(__VA_ARGS__);} while(0)
  #define trca(v,N) do { cout << #v << " = "; array_out(v , N);cout << endl;} while(0)
#else
  #define trc(...)
  #define trca(...)
#endif
using namespace std;
using ll = long long;
using vi = vector<int>;
using vl = vector<ll>;
using vvi = vector< vector<int> >;
constexpr int inf = 1001001001;
constexpr ll infLL = 0x1FFFFFFFFFFFFFFFLL;
struct IoSetupNya {IoSetupNya() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(15); cerr << fixed << setprecision(15);} } iosetupnya;
template<typename T, typename U> inline bool amin(T &x, U y) { return (y < x) ? (x = y, true) : false; }
template<typename T, typename U> inline bool amax(T &x, U y) { return (x < y) ? (x = y, true) : false; }
template<typename T, typename U> ostream& operator <<(ostream& os, const pair<T, U> &p) { os << p.first << " " << p.second; return os; }
template<typename T, typename U> istream& operator >>(istream& is, pair<T, U> &p) { is >> p.first >> p.second; return is; }
template<typename T> ostream& operator <<(ostream& os, const vector<T> &v) { int s = (int)v.size(); rep(i,s) os << (i ? " " : "") << v[i]; return os; }
template<typename T> istream& operator >>(istream& is, vector<T> &v) { for(auto &x : v) is >> x; return is; }
void in(){} template <typename T,class... U> void in(T &t,U &...u){ cin >> t; in(u...);}
void out(){cout << "\n";} template <typename T,class... U> void out(const T &t,const U &...u){ cout << t; if(sizeof...(u)) cout << " "; out(u...);}
template<typename T>void die(T x){out(x); exit(0);}

using P = pair<int,int>;
random_device seed_gen; mt19937_64 mtrand(seed_gen());
constexpr int MOD = 998244353;
//////////////////////////////////////////

void vset(vi &S , vi &v){
  vi c(3 , 0);
  int N = sz(S); N /= 3;
  rep(i,N * 3){
    c[S[i]]++;
    if(c[S[i]] > c[(S[i]+1)%3] && c[S[i]] > c[(S[i]+2)%3]){
      v[i] = 1;
    }
  }
}

int main(){
  ini(N);
  ins(SS);
  vi S(N * 3);
  rep(i , N * 3){
    S[i]=SS[i]=='R' ? 0 : SS[i]=='G' ? 1 : 2;
  }
  vi start(N * 3 , 0) , goal(N * 3 , 0);
  vset(S , start);
  reverse(all(S));
  vset(S , goal);
  reverse(all(goal));
  reverse(all(S));
  trc(start , goal);

  vl v(8 , 0);
  v[0] = N;
  ll ans = 1;
  rep(i,3*N){
    if(start[i]){
      v[0]--;
      v[1<<S[i]]++;
    }
    else if(goal[i]){
      ans = ans * v[7 ^ (1 << S[i])] % MOD;
      v[7]++; v[7 ^ (1 << S[i])]--;
    }
    else{
      ll cur = v[1]+v[2]+v[4]-v[1<<S[i]];
      ans = ans * cur % MOD;
      rep(j,3){
        if(j!=S[i] && v[1<<j] == cur) {
          v[1<<j]--;
          v[(1<<j) | (1<<S[i])]++;
        }
      }
    }
  }
  for(ll i = 1; i <= N; i++){
    ans = ans * i % MOD;
  }
  out(ans);

}

Measured memory_bytes: 4244