#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/hash_policy.hpp>
#define ll long long
#define all(v) v.begin(),v.end()
#define sz(v) ((ll)v.size())
#define V vector
#define vi V<int>
#define vll V<ll>
#define eb emplace_back
#define pii pair<int,int>
#define pll pair<ll,ll>
#define fi first
#define se second
#define A array
#define pb push_back
#define mset multiset
#define gpumap __gnu_pbds::gp_hash_table
#define ccumap __gnu_pbds::cc_hash_table
#define ui unsigned int
#define ull unsigned ll
#define i128 __int128
#define cerr if (test) cerr
#define freopen if (test) freopen
#define whtest if (test)
using namespace std;

const int test = 0;

namespace jhsy {
	constexpr int P = 998244353;
	using i64 = long long;
	template<class T>
	constexpr T power(T a, i64 b) {
		T res = 1;
		for (; b; b /= 2, a *= a) {
			if (b % 2) {
				res *= a;
			}
		}
		return res;
	}
	template<int P>
	struct MInt {
		int x;
		constexpr MInt() : x{} {}
		constexpr MInt(i64 x) : x{norm(x % getMod())} {}
		static int Mod;
		constexpr static int getMod() {
			if (P > 0) {
				return P;
			} else {
				return Mod;
			}
		}
		constexpr static void setMod(int Mod_) {
			Mod = Mod_;
		}
		constexpr int norm(int x) const {
			if (x < 0) {
				x += getMod();
			}
			if (x >= getMod()) {
				x -= getMod();
			}
			return x;
		}
		constexpr int val() const {
			return x;
		}
		explicit constexpr operator int() const {
			return x;
		}
		constexpr MInt operator-() const {
			MInt res;
			res.x = norm(getMod() - x);
			return res;
		}
		constexpr MInt inv() const {
			assert(x != 0);
			return power(*this, getMod() - 2);
		}
		constexpr MInt &operator*=(MInt rhs) & {
			x = 1LL * x * rhs.x % getMod();
			return *this;
		}
		constexpr MInt &operator+=(MInt rhs) & {
			x = norm(x + rhs.x);
			return *this;
		}
		constexpr MInt &operator-=(MInt rhs) & {
			x = norm(x - rhs.x);
			return *this;
		}
		constexpr MInt &operator/=(MInt rhs) & {
			return *this *= rhs.inv();
		}
		friend constexpr MInt operator*(MInt lhs, MInt rhs) {
			MInt res = lhs;
			res *= rhs;
			return res;
		}
		friend constexpr MInt operator+(MInt lhs, MInt rhs) {
			MInt res = lhs;
			res += rhs;
			return res;
		}
		friend constexpr MInt operator-(MInt lhs, MInt rhs) {
			MInt res = lhs;
			res -= rhs;
			return res;
		}
		friend constexpr MInt operator/(MInt lhs, MInt rhs) {
			MInt res = lhs;
			res /= rhs;
			return res;
		}
		friend constexpr std::istream &operator>>(std::istream &is, MInt &a) {
			i64 v;
			is >> v;
			a = MInt(v);
			return is;
		}
		friend constexpr std::ostream &operator<<(std::ostream &os, const MInt &a) {
			return os << a.val();
		}
		friend constexpr bool operator==(MInt lhs, MInt rhs) {
			return lhs.val() == rhs.val();
		}
		friend constexpr bool operator!=(MInt lhs, MInt rhs) {
			return lhs.val() != rhs.val();
		}
	};
	template<>
	int MInt<0>::Mod = 1;
	template<int V, int P>
	constexpr MInt<P> CInv = MInt<P>(V).inv();
	std::vector<int> rev;
	template<int P>
	std::vector<MInt<P>> roots{0, 1};
	template<int P>
	constexpr MInt<P> findPrimitiveRoot() {
		MInt<P> i = 2;
		int k = __builtin_ctz(P - 1);
		while (true) {
			if (power(i, (P - 1) / 2) != 1) {
				break;
			}
			i += 1;
		}
		return power(i, (P - 1) >> k);
	}
	template<int P>
	constexpr MInt<P> primitiveRoot = findPrimitiveRoot<P>();
	template<>
	constexpr MInt<998244353> primitiveRoot<998244353> {31};
	template<int P>
	constexpr void dft(std::vector<MInt<P>> &a) {
		int n = a.size();
		if (int(rev.size()) != n) {
			int k = __builtin_ctz(n) - 1;
			rev.resize(n);
			for (int i = 0; i < n; i++) {
				rev[i] = rev[i >> 1] >> 1 | (i & 1) << k;
			}
		}
		for (int i = 0; i < n; i++) {
			if (rev[i] < i) {
				std::swap(a[i], a[rev[i]]);
			}
		}
		if (roots<P>.size() < n) {
			int k = __builtin_ctz(roots<P>.size());
			roots<P>.resize(n);
			while ((1 << k) < n) {
				auto e = power(primitiveRoot<P>, 1 << (__builtin_ctz(P - 1) - k -
													   1));
				for (int i = 1 << (k - 1); i < (1 << k); i++) {
					roots<P>[2 * i] = roots<P>[i];
					roots<P>[2 * i + 1] = roots<P>[i] * e;
				}
				k++;
			}
		}
		for (int k = 1; k < n; k *= 2) {
			for (int i = 0; i < n; i += 2 * k) {
				for (int j = 0; j < k; j++) {
					MInt<P> u = a[i + j];
					MInt<P> v = a[i + j + k] * roots<P>[k + j];
					a[i + j] = u + v;
					a[i + j + k] = u - v;
				}
			}
		}
	}
	template<int P>
	constexpr void idft(std::vector<MInt<P>> &a) {
		int n = a.size();
		std::reverse(a.begin() + 1, a.end());
		dft(a);
		MInt<P> inv = (1 - P) / n;
		for (int i = 0; i < n; i++) {
			a[i] *= inv;
		}
	}
	template<int P = 998244353>
	struct Poly : public std::vector<MInt<P>> {
		using Value = MInt<P>;
		Poly() : std::vector<Value>() {}
		explicit constexpr Poly(int n) : std::vector<Value>(n) {}
		explicit constexpr Poly(const std::vector<Value> &a) : std::vector<Value>(a)
		{}
		constexpr Poly(const std::initializer_list<Value> &a) : std::vector<Value>
																		(a) {}
		template<class InputIt, class = std::_RequireInputIter<InputIt>>
		explicit constexpr Poly(InputIt first, InputIt last) : std::vector<Value>
																	   (first, last) {}
		template<class F>
		explicit constexpr Poly(int n, F f) : std::vector<Value>(n) {
			for (int i = 0; i < n; i++) {
				(*this)[i] = f(i);
			}
		}
		constexpr Poly shift(int k) const {
			if (k >= 0) {
				auto b = *this;
				b.insert(b.begin(), k, 0);
				return b;
			} else if (this->size() <= -k) {
				return Poly();
			} else {
				return Poly(this->begin() + (-k), this->end());
			}
		}
		constexpr Poly trunc(int k) const {
			Poly f = *this;
			f.resize(k);
			return f;
		}
		constexpr friend Poly operator+(const Poly &a, const Poly &b) {
			Poly res(std::max(a.size(), b.size()));
			for (int i = 0; i < a.size(); i++) {
				res[i] += a[i];
			}
			for (int i = 0; i < b.size(); i++) {
				res[i] += b[i];
			}
			return res;
		}
		constexpr friend Poly operator-(const Poly &a, const Poly &b) {
			Poly res(std::max(a.size(), b.size()));
			for (int i = 0; i < a.size(); i++) {
				res[i] += a[i];
			}
			for (int i = 0; i < b.size(); i++) {
				res[i] -= b[i];
			}
			return res;
		}
		constexpr friend Poly operator-(const Poly &a) {
			std::vector<Value> res(a.size());
			for (int i = 0; i < int(res.size()); i++) {
				res[i] = -a[i];
			}
			return Poly(res);
		}
		constexpr friend Poly operator*(Poly a, Poly b) {
			if (a.size() == 0 || b.size() == 0) {
				return Poly();
			}
			if (a.size() < b.size()) {
				std::swap(a, b);
			}
			int n = 1, tot = a.size() + b.size() - 1;
			while (n < tot) {
				n *= 2;
			}
			if (((P - 1) & (n - 1)) != 0 || b.size() < 128) {
				Poly c(a.size() + b.size() - 1);
				for (int i = 0; i < a.size(); i++) {
					for (int j = 0; j < b.size(); j++) {
						c[i + j] += a[i] * b[j];
					}
				}
				return c;
			}
			a.resize(n);
			b.resize(n);
			dft(a);
			dft(b);
			for (int i = 0; i < n; ++i) {
				a[i] *= b[i];
			}
			idft(a);
			a.resize(tot);
			return a;
		}
		constexpr friend Poly operator*(Value a, Poly b) {
			for (int i = 0; i < int(b.size()); i++) {
				b[i] *= a;
			}
			return b;
		}
		constexpr friend Poly operator*(Poly a, Value b) {
			for (int i = 0; i < int(a.size()); i++) {
				a[i] *= b;
			}
			return a;
		}
		constexpr friend Poly operator/(Poly a, Value b) {
			for (int i = 0; i < int(a.size()); i++) {
				a[i] /= b;
			}
			return a;
		}
		constexpr Poly &operator+=(Poly b) {
			return (*this) = (*this) + b;
		}
		constexpr Poly &operator-=(Poly b) {
			return (*this) = (*this) - b;
		}
		constexpr Poly &operator*=(Poly b) {
			return (*this) = (*this) * b;
		}
		constexpr Poly &operator*=(Value b) {
			return (*this) = (*this) * b;
		}
		constexpr Poly &operator/=(Value b) {
			return (*this) = (*this) / b;
		}
		constexpr Poly deriv() const {
			if (this->empty()) {
				return Poly();
			}
			Poly res(this->size() - 1);
			for (int i = 0; i < this->size() - 1; ++i) {
				res[i] = (i + 1) * (*this)[i + 1];
			}
			return res;
		}
		constexpr Poly integr() const {
			Poly res(this->size() + 1);
			for (int i = 0; i < this->size(); ++i) {
				res[i + 1] = (*this)[i] / (i + 1);
			}
			return res;
		}
	};
	void main() {
		int n; string s;
		cin >> n >> s;
		V<V<pii>> e(n);
		for (int i = 0; i < n-1; i++) {
			int u,v;
			cin >> u >> v; u--; v--;
			e[u].eb(v,0); e[v].eb(u,1);
		}
		vi col(n,-1);
		using Z = MInt<P>;
		V<A<Z,2>> f(n);
		auto dfs = [&](auto &&self,int u,int fa) -> void {
			A<V<Poly<P>>,2> vec;
			for (auto [v,w]:e[u]) {
				if (v != fa) {
					col[v] = w;
					self(self,v,u);
					vec[w].pb({f[v][0],f[v][1]});
				}
			}
			A<Poly<P>,2> g{};
			for (int i = 0; i < 2; i++) {
				if (!vec[i].empty()) {
					auto solve = [&](auto &&self,const auto &vec,int l,int r) -> Poly<P> {
						if (r-l == 1) {
							return vec[l];
						}
						int mid = l+((r-l)>>1);
						return self(self,vec,l,mid)*self(self,vec,mid,r);
					};
					g[i] = solve(solve,vec[i],0,sz(vec[i]));
				}
				else {
					g[i] = {1};
				}
			}
			if (s[u] == 'S') {
				for (int i = 0; i < sz(g[0]); i++) {
					if (i < sz(g[1])) {
						f[u][0] += g[0][i]*g[1][i];
					}
					if (i && i-1 < sz(g[1])) {
						f[u][0] += g[0][i]*g[1][i-1];
					}
				}
				if (col[u] == 0) {
					for (int i = 0; i < sz(g[0]); i++) {
						if (i >= 1 && i-1 < sz(g[1])) {
							f[u][1] += g[0][i]*g[1][i-1];
						}
						if (i >= 2 && i-2 < sz(g[1])) {
							f[u][1] += g[0][i]*g[1][i-2];
						}
					}
				}
				if (col[u] == 1) {
					for (int i = 0; i < sz(g[0]); i++) {
						if (i < sz(g[1])) {
							f[u][1] += g[0][i]*g[1][i];
						}
					}
					for (int i = 1; i < sz(g[1]); i++) {
						if (i-1 < sz(g[0])) {
							f[u][1] += g[0][i-1]*g[1][i];
						}
					}
				}
			}
			else {
				for (int i = 0; i < sz(g[1]); i++) {
					if (i < sz(g[0])) {
						f[u][0] += g[1][i]*g[0][i];
					}
					if (i && i-1 < sz(g[0])) {
						f[u][0] += g[1][i]*g[0][i-1];
					}
				}
				if (col[u] == 0) {
					for (int i = 0; i < sz(g[1]); i++) {
						if (i < sz(g[0])) {
							f[u][1] += g[1][i]*g[0][i];
						}
					}
					for (int i = 1; i < sz(g[0]); i++) {
						if (i-1 < sz(g[1])) {
							f[u][1] += g[1][i-1]*g[0][i];
						}
					}
				}
				if (col[u] == 1) {
					for (int i = 0; i < sz(g[1]); i++) {
						if (i >= 1 && i-1 < sz(g[0])) {
							f[u][1] += g[1][i]*g[0][i-1];
						}
						if (i >= 2 && i-2 < sz(g[0])) {
							f[u][1] += g[1][i]*g[0][i-2];
						}
					}
				}
			}
		};
		dfs(dfs,0,-1);
		cout << f[0][0] << '\n';
	}
}

int main() {
	freopen("test.in","r",stdin);
	freopen("test.out","w",stdout);
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cout << fixed << setprecision(20);

//	jhsy::init();

	int T = 1;
//	cin >> T;
	while (T--) {
		jhsy::main();
	}

	return 0;
}