#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <time.h>
#include <tuple>
#include <utility>
#include <vector>
#define ll long long
#define itn int
#define endl '\n'
#define co(ans) cout<<ans<<endl
#define COYE cout<<"YES"<<endl
#define COYe cout<<"Yes"<<endl
#define COye cout<<"yes"<<endl
#define CONO cout<<"NO"<<endl
#define CONo cout<<"No"<<endl
#define COno cout<<"no"<<endl
#define FORE(i,a) for(auto &i:a)
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define FFOR(i,a,b) for(int i=(a);i<=(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define RREP(i,n)  FFOR(i,1,n)
#define PB push_back
#define MP make_pair
#define ALL(V) (V).begin(),(V).end()
#define SORT(V) sort((V).begin(),(V).end())
#define REVERSE(V) reverse((V).begin(),(V).end())
#define EACH(V,i) for(typeof((V).begin()) i=(V).begin();i!=(V).end();++i)
#define equals(a,b) (fabs((a)-(b))<EPS)
#define INF ((1LL<<62)-(1LL<<31))
#define EPS 1e-10
#define PI 3.141592653589793238
#define MOD 998244353
#define MAX 5100000
using namespace std;
using Graph=vector<vector<int>>;
inline int toInt(string s){int v;istringstream sin(s);sin>>v;return v;}
template<class T>inline string toString(T x){ostringstream sout;sout<<x;return sout.str();}
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;}
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef long long LL;
const int dx[4]={0,1,0,-1},dy[4]={1,0,-1,0};
ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
ll lcm(ll a,ll b){return a/gcd(a,b)*b;}

////////// 二項係数(N<=10^7) //////////

ll fac[MAX],finv[MAX],inv[MAX];
// fac[i] i!
// finv[i] i!の逆元
// inv[i] iの逆元

// テーブルを作る前処理
void COMinit(){
  fac[0]=fac[1]=1;
  finv[0]=finv[1]=1;
  inv[1]=1;
  for(ll i=2; i<MAX; ++i){
    fac[i]=fac[i-1]*i%MOD;
    inv[i]=MOD-inv[MOD%i]*(MOD/i)%MOD;
    finv[i]=finv[i-1]*inv[i]%MOD;
  }
}

// 二項係数計算
ll COM(ll n,ll k){
  if(n<k) return 0;
  if(n<0 || k<0) return 0;
  return fac[n]*(finv[k]*finv[n-k]%MOD)%MOD;
}

//////////////////////////////////////////////////

int main(){
  ll N,ans=1LL;
  string S;
  cin>>N>>S;
  COMinit();
  
  ll DP[10];
  // DP[1] RG
  // DP[2] GB
  // DP[3] BR
  // DP[4] R
  // DP[5] G
  // DP[6] B
  REP(i,10) DP[i]=0;
  
  REP(i,3*N){
    if(S.at(i)=='R'){
      if(DP[2]>0){
        ans*=DP[2];
        ans%=MOD;
        DP[2]--;
      }
      else if(DP[5]>0){
        ans*=DP[5];
        ans%=MOD;
        DP[5]--;
        DP[1]++;
      }
      else if(DP[6]>0){
        ans*=DP[6];
        ans%=MOD;
        DP[6]--;
        DP[3]++;
      }
      else DP[4]++;
    }
    if(S.at(i)=='G'){
      if(DP[3]>0){
        ans*=DP[3];
        ans%=MOD;
        DP[3]--;
      }
      else if(DP[4]>0){
        ans*=DP[4];
        ans%=MOD;
        DP[4]--;
        DP[1]++;
      }
      else if(DP[6]>0){
        ans*=DP[6];
        ans%=MOD;
        DP[6]--;
        DP[2]++;
      }
      else DP[5]++;
    }
    if(S.at(i)=='B'){
      if(DP[1]>0){
        ans*=DP[1];
        ans%=MOD;
        DP[1]--;
      }
      else if(DP[4]>0){
        ans*=DP[4];
        ans%=MOD;
        DP[4]--;
        DP[3]++;
      }
      else if(DP[5]>0){
        ans*=DP[5];
        ans%=MOD;
        DP[5]--;
        DP[2]++;
      }
      else DP[6]++;
    }
  }
  
  ans*=fac[N];
  ans%=MOD;
  if(ans<0) ans+=MOD;
  co(ans);
  return 0;
}

Measured memory_bytes: 120196