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

using Poly = vector<int>;
const int MXN = (1 << 19);
const int DVS = 998244353;
const int G = 3;
const int Gi = 332748118;
int N, tgt[MXN], bse[MXN], ibse[MXN];
bool tp[MXN];
Poly res[MXN], arr[MXN];
vector<pair<int, bool>> to[MXN];

int pw(int b, int p) {
  int a(1);
  while (p) {
    if (p & 1) a = a * 1LL * b % DVS;
    b = b * 1LL * b % DVS;
    p >>= 1;
  }
  return a;
}
void pre(int len) {
  for (int i(1); i != len; i <<= 1) {
    for (int j(0); j != i; ++j) {
      bse[i + j] = pw(G, (DVS - 1) / (i * 2) * j);
      ibse[i + j] = pw(Gi, (DVS - 1) / (i * 2) * j);
    }
  }
  for (int i(1); i != len; ++i) {
    tgt[i] = (tgt[i >> 1] >> 1) | (i & 1 ? len >> 1 : 0);
  }
}
void fft(Poly& a, int l, bool tp) {
  for (int i(1); i != l; ++i) if (i < tgt[i]) swap(a[i], a[tgt[i]]);
  for (int i(1); i != l; i <<= 1) {
    for (int j(0); j != l; j += i << 1) {
      for (int k(0); k != i; ++k) {
        int tmp((tp ? ibse : bse)[i + k] * 1LL * a[j + i + k] % DVS);
        a[j + i + k] = (a[j + k] - tmp + DVS) % DVS;
        a[j + k] = (a[j + k] + tmp) % DVS;
      }
    }
  }
  if (tp) {
    int inv(pw(l, DVS - 2));
    for (int i(0); i != l; ++i) a[i] = a[i] * 1LL * inv % DVS;
  }
}

void multi(int l, int r) {
  if (r - l == 1) return;
  int m((l + r) >> 1);
  multi(l, m), multi(m, r);
  int len(1);
  while (len < arr[l].size() + arr[m].size()) len <<= 1;
  arr[l].resize(len), arr[m].resize(len);
  pre(len), fft(arr[l], len, 0), fft(arr[m], len, 0);
  for (int i(0); i != len; ++i) arr[l][i] = arr[l][i] * 1LL * arr[m][i] % DVS;
  fft(arr[l], len, 1);
  while (!arr[l].empty() && !arr[l].back()) arr[l].pop_back();
}

void solve(int p, int f) {
  for (auto pr : to[p]) {
    int q(pr.first);
    if (q == f) continue;
    solve(q, p);
  }
  arr[0].resize(3);
  arr[0][tp[p] ? 2 : 0] = 0;
  arr[0][tp[p] ? 0 : 2] = arr[0][1] = 1;
  int cnt(1);
  for (auto pr : to[p]) {
    int q(pr.first);
    if (q == f) continue;
    arr[cnt] = res[q];
    arr[cnt++][pr.second ? 2 : 0] = 0;
  }
  multi(0, cnt);
  res[p].resize(3);
  res[p][0] = arr[0][cnt - 1];
  res[p][1] = arr[0][cnt];
  res[p][2] = arr[0][cnt + 1];
//  cerr << p << ':' << res[p][0] << ',' << res[p][1] << ',' << res[p][2] << endl;
}

int main() {
  cin >> N;
  for (int i(0); i != N; ++i) {
    char c(0);
    cin >> c;
    tp[i] = (c == 'S');
  }
  for (int i(1), x(0), y(0); i != N; ++i)
    cin >> x >> y, --x, --y,
    to[x].push_back(make_pair(y, 0)),
    to[y].push_back(make_pair(x, 1));
  solve(0, -1);
  cout << res[0][1] << endl;
  return 0;
}