//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,fma,abm,mmx,avx,avx2,tune=native")
#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#ifdef rd
#define trace(...) cout<<"Line:"<<__LINE__<<" "; __f(#__VA_ARGS__, __VA_ARGS__)
template<typename Arg1>
void __f(const char *name, Arg1 &&arg1) {
	cout<<name<<" : "<<arg1<<endl;
}
template<typename Arg1, typename ... Args>
void __f(const char *names, Arg1 &&arg1, Args &&... args) {
	const char *comma=strchr(names+1,',');
	cout.write(names,comma-names)<<" : "<<arg1<<" | ";
	__f(comma+1,args...);
}
#else
#define trace(...)
#define endl '\n'
#endif
#define pb push_back
#define fi first
#define se second
#define int long long
typedef long long ll;
typedef float f80;
#define double long double
#define pii pair<int,int>
#define pll pair<ll,ll>
#define sz(x) ((long long)x.size())
#define fr(a,b,c) for(int a=b; a<=c; a++)
#define rep(a,b,c) for(int a=b; a<c; a++)
#define trav(a,x) for(auto &a:x)
#define all(con) con.begin(),con.end()
const ll infl=0x3f3f3f3f3f3f3f3fLL;
const int infi=0x3f3f3f3f;
const int mod=998244353;
//const int mod=1000000007;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef tree<pii, null_type, less<pii>, rb_tree_tag, tree_order_statistics_node_update> oset;
auto clk=clock();
mt19937_64 rang(chrono::high_resolution_clock::now().time_since_epoch().count());
int rng(int lim) {
	uniform_int_distribution<int> uid(0,lim-1);
	return uid(rang);
}

int powm(int a, int b) {
	int res=1;
	while(b) {
		if(b&1)
			res=(res*a)%mod;
		a=(a*a)%mod;
		b>>=1;
	}
	return res;
}

int dp[8];
void solve() {
	int n;
	string s;
	cin>>n>>s;
	for(char &i:s)
		if(i=='R')
			i=0;
		else if(i=='G')
			i=1;
		else
			i=2;
	int r=0,g=0,b=0,br=0,rb=0,gb=0,bg=0,rg=0,gr=0;
	int ans=1;
	queue<char> tol;
	for(int i=0; i<3*n; i++) {
		if(s[i]==0) {
			r++;
			if(bg>=r) {
				ans=(ans*(bg+gb))%mod;
				bg--;
				r--;
			}
			else if(gb>=r) {
				ans=(ans*gb)%mod;
				gb--;
				r--;
			}
			else if(b>=r) {
				br++;
				ans=(ans*(b+g))%mod;
				b--;
				r--;
			} else if(g>=r) {
				gr++;
				ans=(ans*g)%mod;
				g--;
				r--;
			}
		} else if(s[i]==1) {
			g++;
			if(br>=g) {
				ans=(ans*(br+rb))%mod;
				br--;
				g--;
			}
			else if(rb>=g) {
				ans=(ans*rb)%mod;
				rb--;
				g--;
			}
			else if(b>=g) {
				bg++;
				ans=(ans*(b+r))%mod;
				b--;
				g--;
			} else if(r>=g) {
				rg++;
				ans=(ans*r)%mod;
				r--;
				g--;
			}
		} else {
			b++;
			if(gr>=b) {
				ans=(ans*(gr+rg))%mod;
				gr--;
				b--;
			}
			else if(rg>=b) {
				ans=(ans*rg)%mod;
				rg--;
				b--;
			}
			else if(g>=b) {
				gb++;
				ans=(ans*(r+g))%mod;
				g--;
				b--;
			} else if(r>=b) {
				rb++;
				ans=(ans*r)%mod;
				r--;
				b--;
			}
		}
	}
	for(int i=1; i<=n; i++)
		ans=(ans*i)%mod;
	cout<<ans<<endl;
}

signed main() {
	ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0);
	srand(chrono::high_resolution_clock::now().time_since_epoch().count());
	cout<<fixed<<setprecision(10);
	int t=1;
//	cin>>t;
	while(t--)
		solve();
#ifdef rd
	cout<<endl<<endl<<endl<<endl<<"Time elapsed: "<<(double)(clock()-clk)/CLOCKS_PER_SEC<<endl;
#endif
	return 0;
}


Measured memory_bytes: 720