#include "bits/stdc++.h"
using namespace std;
#ifdef _DEBUG
#include "dump.hpp"
#else
#define dump(...)
#endif

//#define int long long
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define all(c) begin(c),end(c)
const int INF = sizeof(int) == sizeof(long long) ? 0x3f3f3f3f3f3f3f3fLL : 0x3f3f3f3f;
const int MOD = 1'000'000'007;
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } return false; }

template<typename T>
vector<T> gen_v(size_t a) { return vector<T>(a); }
template<typename T, typename ...Ts>
auto gen_v(size_t a, Ts... ts) { return vector<decltype(gen_v<T>(ts...))>(a, gen_v<T>(ts...)); }
template<typename T, typename V>
typename enable_if<is_class<T>::value == 0>::type
fill_v(T & t, const V & v) { t = v; }
template<typename T, typename V>
typename enable_if<is_class<T>::value != 0>::type
fill_v(T & t, const V & v) { for (auto& e : t) fill_v(e, v); }

template<int MOD>
struct ModInt {
	static const int kMod = MOD;
	unsigned x;
	ModInt() :x(0) {}
	ModInt(signed x_) { x_ %= MOD; if (x_ < 0)x_ += MOD; x = x_; }
	ModInt(signed long long x_) { x_ %= MOD; if (x_ < 0)x_ += MOD; x = x_; }
	int get()const { return (int)x; }
	ModInt& operator+=(ModInt m) { if ((x += m.x) >= MOD)x -= MOD; return *this; }
	ModInt& operator-=(ModInt m) { if ((x += MOD - m.x) >= MOD)x -= MOD; return *this; }
	ModInt& operator*=(ModInt m) { x = (unsigned long long)x * m.x % MOD; return *this; }
	ModInt& operator/=(ModInt m) { return *this *= m.inverse(); }
	ModInt operator+(ModInt m)const { return ModInt(*this) += m; }
	ModInt operator-(ModInt m)const { return ModInt(*this) -= m; }
	ModInt operator*(ModInt m)const { return ModInt(*this) *= m; }
	ModInt operator/(ModInt m)const { return ModInt(*this) /= m; }
	ModInt operator-()const { return ModInt(MOD - (signed)x); }
	bool operator==(ModInt m)const { return x == m.x; }
	bool operator!=(ModInt m)const { return x != m.x; }
	ModInt inverse()const {
		signed a = x, b = MOD, u = 1, v = 0;
		while (b) {
			signed t = a / b;
			a -= t * b; swap(a, b);
			u -= t * v; swap(u, v);
		}
		if (u < 0)u += MOD;
		return ModInt(u);
	}
};
template<int MOD>
ostream& operator<<(ostream& os, const ModInt<MOD>& m) { return os << m.x; }
template<int MOD>
istream& operator>>(istream& is, ModInt<MOD>& m) { signed long long s; is >> s; m = ModInt<MOD>(s); return is; };

template<int MOD>
ModInt<MOD> pow(ModInt<MOD> a, unsigned long long k) {
	ModInt<MOD> r = 1;
	while (k) {
		if (k & 1)r *= a;
		a *= a;
		k >>= 1;
	}
	return r;
}

using mint = ModInt<MOD>;



signed main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int N; cin >> N;
	string S; cin >> S;
	
	int M = 2 * N;
	string T = S;

	rep(i, 0, M) {
		if (S[i] == 'B') {
			if (i % 2) {
				T[i] = ')';
			}
			else {
				T[i] = '(';
			}
		}
		else {
			if (i % 2) {
				T[i] = '(';
			}
			else {
				T[i] = ')';
			}
		}
	}
	dump(T);

	mint ans = 1;
	int cnt = 0;
	bool f = true;
	rep(i, 0, M) {
		if (T[i] == '(')cnt++;
		else {
			ans *= cnt;
			cnt--;
		}
		dump(cnt, ans);
		if (cnt < 0)f = false;
	}
	if (cnt != 0)f = false;

	rep(i, 1, N + 1)ans *= i;

	if (f)cout << ans << endl;
	else cout << 0 << endl;
	return 0;
}

Measured memory_bytes: 788