#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <stack>
#include <queue>
#include <cmath>
#include <tuple>
#include <cstdio>
#include <bitset>
#include <sstream>
#include <iterator>
#include <numeric>
#include <map>
#include <cstring>
#include <set>
#include <functional>
#include <iomanip>

using namespace std;

#define DEBUG_ //!!提出時にコメントアウト!!
#ifdef DEBUG_
	#define dump(x)  cerr << #x << " = " << (x) << endl;
#else
	#define dump(x)  ;
#endif

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define SZ(x) ((int)(x).size())
#define pb push_back
#define eb emplace_back

//#define int long long

typedef long long LL;
typedef vector<int> VI;
typedef vector<LL> VL;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef pair<LL, LL> PLL;

template <typename T>
std::string printVector(const std::vector<T> &data)
{
    std::stringstream ss;
    std::ostream_iterator<T> out_it(ss, ", ");
    ss << "[";
    std::copy(data.begin(), data.end() - 1, out_it);
    ss << data.back() << "]";
    return ss.str();
}

const int mod = 1e9+7;
const LL LINF = 1001002003004005006ll;
const int INF = 1001001001;

struct mint {
    LL x; // typedef long long LL;
    mint(LL x=0):x(x%mod){}
    mint& operator+=(const mint a) {
      if ((x += a.x) >= mod) x -= mod;
      return *this;
    }
    mint& operator-=(const mint a) {
      if ((x += mod-a.x) >= mod) x -= mod;
      return *this;
    }
    mint& operator*=(const mint a) {
      (x *= a.x) %= mod;
      return *this;
    }
    mint operator+(const mint a) const {
      mint res(*this);
      return res+=a;
    }
    mint operator-(const mint a) const {
      mint res(*this);
      return res-=a;
    }
    mint operator*(const mint a) const {
      mint res(*this);
      return res*=a;
    }
    mint pow(LL t) const {
      if (!t) return 1;
      mint a = pow(t>>1);
      a *= a;
      if (t&1) a *= *this;
      return a;
    }

    // for prime mod
    mint inv() const {
      return pow(mod-2);
    }
    mint& operator/=(const mint a) {
      return (*this) *= a.inv();
    }
    mint operator/(const mint a) const {
      mint res(*this);
      return res/=a;
    }
  };

signed main(int argc, char const *argv[])
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N; cin >> N;
    string S; cin >> S;

    string S1;
    S1 = S + "W";

    if(S1[0] != 'B' || S1[2*N-1] != 'B'){
        cout << 0 << endl;
        return 0;
    }

    char pre = 'L';
    string state = "L";

    FOR(i,1,2*N){
        if(S1[i] == S[i-1]){
            if(pre == 'L'){
                state += 'R';
                pre = 'R';
            }else{
                state += 'L';
                pre = 'L';
            }
        }else{
            if(pre == 'L'){
                state += 'L';
                pre = 'L';
            }else{
                state += 'R';
                pre = 'R';
            }
        }
    }
    bool ok = 1;
    int lcnt = 0, rcnt = 0;
    REP(i,2*N){
        if(state[i] == 'L') lcnt++;
        else rcnt++;
    }
    if(lcnt != rcnt) ok = 0;
    if(state[2*N-1] != 'R') ok = 0;
    if(!ok){
        cout << 0 << endl;
        return 0;
    }

    lcnt = 0; rcnt = 0;
    mint ans = 1;
    REP(i,2*N){
        if(state[i] == 'L'){
            lcnt++;
        }
        else{
            if(lcnt <= 0){
                cout << 0 << endl;
                return 0;
            }
            ans *= lcnt;
            lcnt--;
        }
    }
    FOR(i,1,N+1){
        ans *= i;
    }
    cout << ans.x << endl;


}


Measured memory_bytes: 1044