#include <bits/stdc++.h>
using namespace std;

#define REP(i,m,n) for(int i=(m); i<(int)(n); i++)
#define RREP(i,m,n) for(int i=(int)(n-1); i>=m; i--)
#define rep(i,n) REP(i,0,n)
#define rrep(i,n) RREP(i,0,n)
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
#define fi first
#define se second
#define debug(...) {cerr<<"[L"<<__LINE__<<"] "; _debug(__VA_ARGS__);}

template<typename T>
string join(const vector<T>&v, string del=", "){ stringstream s;
    for(auto x : v) s << del << x; return s.str().substr(del.size());
}
template<typename T>
ostream& operator<<(ostream& o, const vector<T>&v){
    if(v.size()) o << "[" << join(v) << "]"; return o;
}
template<typename T>
ostream& operator<<(ostream& o, const vector<vector<T> >&vv){
    int l = vv.size();
    if(l){ o<<endl; rep(i,l) o << (i==0 ? "[ " : ",\n  " ) << vv[i] << (i==l-1 ? " ]" : ""); }
    return o;
}
template<typename T1, typename T2>
ostream& operator<<(ostream& o, const pair<T1, T2>& p){
    return o << "(" << p.first << ", " << p.second << ")";
}
inline void _debug(){cerr<<endl;}
template<class First, class... Rest>
void _debug(const First& first, const Rest&... rest){cerr<<first<<" ";_debug(rest...);}

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<vl> vvl;

const double PI = (1*acos(0.0));
const double EPS = 1e-9;
const int INF = 0x3f3f3f3f;
const ll INFL = 0x3f3f3f3f3f3f3f3fLL;
const ll mod = 1e9 + 7;

inline void finput(string filename) {
    freopen(filename.c_str(), "r", stdin);
}

int main(){
    ios_base::sync_with_stdio(0);
    // finput("./input");
    int n; cin >> n;
    string s; cin >> s;
    if(s[0] == 'W'){
        cout << 0 << endl;
        return 0;
    }

    vi a(2*n);
    a[0] = 0;
    REP(i,1,2*n){
        if(s[i] != s[i-1]){
            a[i] = a[i-1];
        }else{
            a[i] = a[i-1] ^ 1;
        }
    }
    ll cnt = 0;
    ll ans = 1;
    rep(i,2*n){
        if(a[i] == 1){
            ans *= cnt;
            ans %= mod;
            cnt--;
        }else{
            cnt++;
        }
        if(cnt < 0){
            cout << 0 << endl;
            return 0;
        }
    }
    if(cnt != 0){
        cout << 0 << endl;
    }else{
        rep(i,n){
            ans *= i+1;
            ans %= mod;
        }
        cout << ans << endl;
    }
    return 0;
}
//g++ -std=c++14 test.cpp -o test.out
//問題URL
//https://atcoder.jp/contests/jsc2019-qual/tasks/jsc2019_qual_c
//左端、右端を選んで操作、という操作は
//まず左端のみに注目し、次に右端のみに注目していく
//また最左端にまとめるなんて考え方も
#include <string.h>
#include <stdlib.h>
#include <math.h>
#include <cassert>
#include <algorithm>
#include <functional>
#include <iostream>
#include <iomanip>
#include <vector>
#include <queue>
#include <map> 
#include <utility>
#include <limits.h>
#include <bitset>
#include <set>
using namespace std;
 
#define LL long long int
const LL INF = (LL)(1e18)+1;
const int INF_INT = 2147483647-1e6;
const LL mod = 1000000007ll;

int N;
string S;

LL ans = 1;

void solve(){
	int cur = 0;
	for(int i=0;i<2*N;i++){
		if(S[i]=='B'){
			if(cur%2==1){
				ans = ans*cur%mod;
				cur--;
			}else{
				cur++;
			}
		}
		if(S[i]=='W'){
			if(cur%2==1){
				cur++;
			}else{
				ans = ans*cur%mod;
				cur--;
			}
		}
	}
	if(cur>0) ans = 0;
	for(int i=0;i<N;i++) ans = ans*(i+1)%mod;
}
 
int main(){
	cin >> N;
	cin >> S;
 
	solve();

	cout << ans << endl;
	return 0;
}