//g++ 6.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);

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

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

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

  mint rr=1,bb=1,rb=0,sum=0,sum2=0;

  rep(i,1,5){
    rr*=r-i+1;
    bb*=b-i+1;
    rr/=i,bb/=i;
  }
  rr*=fac(r-5)*fac(b-1);
  bb*=fac(r-1)*fac(b-5);

  if(r==0||b==0){
    rr+=bb;
    cout<<rr.val()<<endl;
    return 0;
  }

  rep(i,1,r){
    ll p,q;
    p=red[i]-red[0];
    q=b-p;
    sum+=p*q;
    sum2+=p-q;
  }
  rb+=sum;

  rep(i,1,r){
    ll p,q;
    p=red[i]-red[0];
    q=b-p;
    sum-=p*q;
    sum2-=p-q;
    ll c=red[i]-red[0];
    rb+=sum+sum2*c-c*c*(r-i-1);
  }
  rb*=fac(r-3)*fac(b-3);

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