//g++ 5.cpp -std=c++14 -O2 -I .
#include <bits/stdc++.h>
using namespace std;

#include <atcoder/all>
using namespace atcoder;

using ll = long long;
using ld = long double;

using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using vld = vector<ld>;
using vvld = vector<vld>;

#define fi first
#define se second
#define pb push_back
#define pq_big(T) priority_queue<T,vector<T>,less<T>>
#define pq_small(T) priority_queue<T,vector<T>,greater<T>>
#define all(a) a.begin(),a.end()
#define rep(i,start,end) for(ll i=start;i<(ll)(end);i++)
#define per(i,start,end) for(ll i=start;i>=(ll)(end);i--)

using mint = modint998244353;

//n!!
mint fac(int n){
  if(n<=0){
    return 1;
  }
  mint res=1;
  return res*n*fac(n-2);
}

int main(){
  ios::sync_with_stdio(false);
  cin.tie(nullptr);

  mint rr=0,bb=0,rb=0;

  int n;
  string s;
  cin>>n>>s;

  int r=0,b=0;
  rep(i,0,2*n){
    if(s[i]=='R'){
      r++;
    }
    else{
      b++;
    }
  }

  if(r%2==1){
    cout<<0<<endl;
    return 0;
  }

  rep(i,0,2*n){
    rep(j,i+1,2*n){
      rep(k,j+1,2*n){
        rep(l,k+1,2*n){
          int r2=0;

          if(s[i]=='R')r2++;
          if(s[j]=='R')r2++;
          if(s[k]=='R')r2++;
          if(s[l]=='R')r2++;

          if(r2%2==1)continue;

          if(r2==2){
            if(s[i]==s[j])continue;
            if(s[j]==s[k])continue;
            if(s[k]==s[l])continue;
            if(s[l]==s[i])continue;

            rb+=fac(r-3)*fac(b-3);
          }
          else if(r2==4){
            rr+=fac(r-5)*fac(b-1);
          }
          else{
            bb+=fac(r-1)*fac(b-5);
          }

        }
      }
    }
  }
  
  mint ans=rr+bb+rb;
  cout<<ans.val()<<endl;
}