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

using ll = long long;
#define int ll
#define pb push_back
#define all(v) (v).begin(), (v).end()

void dbg_out() { cerr << endl; }
template<typename H, typename... T>
void dbg_out(H h, T... t) { cerr << ' ' << h; dbg_out(t...); }
#define dbg(...) { cerr << #__VA_ARGS__ << ':'; dbg_out(__VA_ARGS__); }

template<int MOD>
struct mint {
	int x;
	mint(): x(0) {}
	mint(int _x): x(_x%MOD < 0 ? _x%MOD + MOD : _x%MOD) {}
	mint& operator+=(mint rhs) { x += rhs.x; if( x >= MOD ) x -= MOD; return *this; }
	mint& operator-=(mint rhs) { x -= rhs.x; if( x < 0 ) x += MOD; return *this; }
	mint& operator*=(mint rhs) { x = x * rhs.x % MOD; return *this; }
	mint& operator/=(mint rhs) { return this *= rhs.inv(); }
	mint operator+(mint rhs) { mint m = *this; return m += rhs; }
	mint operator-(mint rhs) { mint m = *this; return m -= rhs; }
	mint operator*(mint rhs) { mint m = *this; return m *= rhs; }
	mint operator/(mint rhs) { mint m = *this; return m /= rhs; }
	mint inv() { return this->pow(MOD-2); }
	mint pow(int e) {
		mint ret = 1;
		for(mint p = *this; e > 0; e /= 2, p *= p) if(e & 1)
			ret *= p;
		return ret;
	}
};


using Z = mint<998244353>;
namespace NTT {
	const Z root (15311432), root_1(469870224);
	int root_pw = 1 << 23;

	void fft(vector<Z>& a, bool invert) {
		int n = a.size();
		for(int i=1,j=0;i<n;i++) {
			int bit = n >> 1;
			for(; j & bit; bit >>= 1)
				j ^= bit;
			j ^= bit;
			if(i < j) swap(a[i], a[j]);
		}
		for(int len = 2; len <= n; len <<= 1) {
			Z wlen = invert ? root_1 : root;
			for(int i = len; i < root_pw; i <<= 1)
				wlen *= wlen;
			for(int i = 0; i < n; i += len) {
				Z w(1);
				for(int j=0;j<len/2;j++) {
					Z u = a[i+j], v = a[i+j+len/2] * w;
					a[i+j] = u + v;
					a[i + j + len/2] = u - v;
					w *= wlen;
				}
			}
		}
		if(invert) {
			Z n_1 = Z(n).inv();
			for(Z& x: a) x *= n_1;
		}
	}

	vector<Z> multiply(vector<Z>& a, vector<Z> &b) {
		vector<Z> fa = a, fb = b;
		int sz = a.size() + b.size() - 1, n = 1;
		while(n < sz) n <<= 1;

		fa.resize(n), fb.resize(n);
		fft(fa, 0), fft(fb, 0);
		for(int i=0;i<fa.size();i++) fa[i] *= fb[i];
		fft(fa, 1);
		fa.resize(sz);
		return fa;
	}
}

vector<pair<int,int>> ed;
const int MAXN = 2e5+5;
vector<pair<int,int>> g[MAXN];
string s;

Z dp[MAXN][2];

void dfs(int u, int p){
	int cnt = 0;
	for(auto [v,id] : g[u]) if(v != p){
		dfs(v,u);
		cnt++;
	}
	if(cnt == 0){
		dp[u][0] = Z(1);
		int id = g[u][0].second;
		if(s[u] == 'F' && ed[id].first == p){
			dp[u][1] = Z(1);
		}
		if(s[u] == 'S' && ed[id].second == p){
			dp[u][1] = Z(1);
		}
		return;
	}
	vector<vector<Z>> entra, sai;
	for(auto [v,id] : g[u]) if(v != p){
		vector<Z> aq = {dp[v][0],dp[v][1]};
		if(ed[id].first == u){
			sai.push_back(aq);
		}else{
			entra.push_back(aq);
		}
	}
	vector<Z> base = {Z(1)};
	entra.push_back(base);
	sai.push_back(base);

	auto uni = [&](vector<vector<Z>> a){
		while(int32_t(a.size()) >= 2){
			vector<vector<Z>> nx;
			int n = a.size();
			for(int i = 0; i < n; i += 2){
				if(i == n-1){
					nx.push_back(a[i]);
					continue;
				}
				nx.push_back(NTT::multiply(a[i],a[i+1]));
			}
			a = nx;
		}
		return a[0];
	};

	vector<Z> a = uni(entra);
	vector<Z> b = uni(sai);
	int sza = a.size();
	int szb = b.size();
	int tam = min(sza,szb)+2;
	a.resize(tam,Z(0));
	b.resize(tam,Z(0));

	//nao usa pai, nao inicia caminho
	
	for(int i = 0; i < tam; i++){
		dp[u][0] += a[i]*b[i];
	}

	//nao usa pai, comeca caminho
	if(s[u] == 'S'){
		for(int i = 0; i < tam-1; i++){
			dp[u][0] += a[i]*b[i+1];
		}
	}else{
		for(int i = 0; i < tam-1; i++){
			dp[u][0] += a[i+1]*b[i];
		}
	}
	

	if(u == p) return;
	//usa pai, nao comeca caminho
	int id = 0;
	for(auto [v,ID] : g[u]) if(v == p){
		id = ID;
		break;
	}
	if(ed[id].first == u){
		for(int i = 0; i < tam-1; i++){
			dp[u][1] += a[i+1]*b[i];
		}
	}else{
		for(int i = 0; i < tam-1; i++){
			dp[u][1] += a[i]*b[i+1];
		}
	}

	//usa pai, comeca caminho

	if(ed[id].first == u){
		if(s[u] == 'S'){
			for(int i = 0; i < tam; i++){
				dp[u][1] += a[i]*b[i];
			}
		}else{
			for(int i = 0; i < tam-2; i++){
				dp[u][1] += a[i+2]*b[i];
			}
		}
	}else{
		if(s[u] == 'S'){
			for(int i = 0; i < tam-2; i++){
				dp[u][1] += a[i]*b[i+2];
			}
		}else{
			for(int i = 0; i < tam; i++){
				dp[u][1] += a[i]*b[i];
			}
		}
	}
}

void solve() {
	int n;
	cin >> n;
	cin >> s;
	for(int i = 0; i < n-1; i++){
		int u,v;
		cin >> u >> v;
		u--;
		v--;
		ed.push_back({u,v});
		g[u].push_back({v,i});
		g[v].push_back({u,i});
	}
	dfs(0,0);
	int ans =dp[0][0].x;
	cout << ans << '\n';
	
}

signed main() {
	ios::sync_with_stdio(false); cin.tie(0);
	solve();
}