#include <bits/stdc++.h>
#ifdef dbg
#define D(...) fprintf(stderr, __VA_ARGS__)
#define DD(...) D("[Debug] "#__VA_ARGS__ " = "), \
              debug_helper::debug(__VA_ARGS__), D("\n")
#include "C:\Users\wsyear\Desktop\OI\templates\debug.hpp"
#else
#define D(...) ((void)0)
#define DD(...) ((void)0)
#endif
#define rep(i, j, k) for (int i = (j); i <= (k); ++i)
#define per(i, j, k) for (int i = (j); i >= (k); --i)
#define SZ(v) int((v).size())
#define ALL(v) (v).begin(),(v).end()
#define fi first
#define se second
using ll = long long;
using pii = std::pair<int, int>;
using pll = std::pair<ll, ll>;

template<class T> void chkmn(T &x, T y) { if (y < x) x = y; }
template<class T> void chkmx(T &x, T y) { if (y > x) x = y; }

using namespace std;

template <int P>
class mod_int {
	using Z = mod_int;

private:
	static int mo(int x) { return x < 0 ? x + P : x; }

public:
	int x;
	int val() const { return x; }
	mod_int() : x(0) {}
	template <class T>
	mod_int(const T &x_) : x(x_ >= 0 && x_ < P ? static_cast<int>(x_) : mo(static_cast<int>(x_ % P))) {}
	bool operator==(const Z &rhs) const { return x == rhs.x; }
	bool operator!=(const Z &rhs) const { return x != rhs.x; }
	Z operator-() const { return Z(x ? P - x : 0); }
	Z pow(long long k) const {
		Z res = 1, t = *this;
		while (k) {
			if (k & 1) res *= t;
			if (k >>= 1) t *= t;
		}
		return res;
	}
	Z &operator++() {
		x < P - 1 ? ++x : x = 0;
		return *this;
	}
	Z &operator--() {
		x ? --x : x = P - 1;
		return *this;
	}
	Z operator++(int) {
		Z ret = x;
		x < P - 1 ? ++x : x = 0;
		return ret;
	}
	Z operator--(int) {
		Z ret = x;
		x ? --x : x = P - 1;
		return ret;
	}
	Z inv() const { return pow(P - 2); }
	Z &operator+=(const Z &rhs) {
		(x += rhs.x) >= P && (x -= P);
		return *this;
	}
	Z &operator-=(const Z &rhs) {
		(x -= rhs.x) < 0 && (x += P);
		return *this;
	}
	Z &operator*=(const Z &rhs) {
		x = 1ULL * x * rhs.x % P;
		return *this;
	}
	Z &operator/=(const Z &rhs) { return *this *= rhs.inv(); }
#define setO(T, o)                                 \
	friend T operator o(const Z &lhs, const Z &rhs) {\
		Z res = lhs;                                   \
		return res o## = rhs;                          \
	}
	setO(Z, +) setO(Z, -) setO(Z, *) setO(Z, /)
#undef setO
};
const int P = 998244353;
using Z = mod_int<P>;

namespace Poly_space {
std::vector<int> rev;
std::vector<Z> roots{0, 1};
void dft(std::vector<Z> &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 ? 1 << k : 0);
    }
  }
  for (int i = 0; i < n; i++)
    if (rev[i] < i) std::swap(a[i], a[rev[i]]);
  if (int(roots.size()) < n) {
    int k = __builtin_ctz(roots.size());
    roots.resize(n);
    while ((1 << k) < n) {
      Z e = Z(3).pow((P - 1) >> (k + 1));
      for (int i = 1 << (k - 1); i < (1 << k); i++)
        roots[2 * i] = roots[i], roots[2 * i + 1] = roots[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++) {
        Z u = a[i + j], v = a[i + j + k] * roots[k + j];
        a[i + j] = u + v, a[i + j + k] = u - v;
      }
}
void idft(std::vector<Z> &a) {
  int n = a.size();
  std::reverse(a.begin() + 1, a.end());
  dft(a);
  Z inv = (1 - P) / n;
  for (int i = 0; i < n; i++) a[i] *= inv;
}
struct Poly {
  std::vector<Z> a;
  Poly() {}
  Poly(const std::vector<Z> &a) : a(a) {}
  Poly(const std::initializer_list<Z> &a) : a(a) {}
  int size() const { return a.size(); }
  void resize(int n) { a.resize(n); }
  Z operator[](int idx) const {
    if (idx < 0 || idx >= size()) return 0;
    return a[idx];
  }
  Z &operator[](int idx) { return a[idx]; }
  Poly mulxk(int k) const {
    auto b = a;
    b.insert(b.begin(), k, 0);
    return Poly(b);
  }
  Poly modxk(int k) const {
    k = std::min(k, size());
    return Poly(std::vector<Z>(a.begin(), a.begin() + k));
  }
  Poly divxk(int k) const {
    if (size() <= k) return Poly();
    return Poly(std::vector<Z>(a.begin() + k, a.end()));
  }
  friend Poly operator+(const Poly &a, const Poly &b) {
    std::vector<Z> res(std::max(a.size(), b.size()));
    for (int i = 0; i < int(res.size()); i++) res[i] = a[i] + b[i];
    return Poly(res);
  }
  friend Poly operator-(const Poly &a, const Poly &b) {
    std::vector<Z> res(std::max(a.size(), b.size()));
    for (int i = 0; i < int(res.size()); i++) res[i] = a[i] - b[i];
    return Poly(res);
  }
  friend Poly operator*(Poly a, Poly b) {
    if (a.size() == 0 || b.size() == 0) return Poly();
    int sz = 1, tot = a.size() + b.size() - 1;
    while (sz < tot) sz *= 2;
    a.a.resize(sz), b.a.resize(sz), dft(a.a), dft(b.a);
    for (int i = 0; i < sz; ++i) a.a[i] = a[i] * b[i];
    idft(a.a), a.resize(tot);
    return a;
  }
  friend Poly operator*(Z a, Poly b) {
    for (int i = 0; i < int(b.size()); i++) b[i] *= a;
    return b;
  }
  friend Poly operator*(Poly a, Z b) {
    for (int i = 0; i < int(a.size()); i++) a[i] *= b;
    return a;
  }
  Poly &operator+=(Poly b) { return (*this) = (*this) + b; }
  Poly &operator-=(Poly b) { return (*this) = (*this) - b; }
  Poly &operator*=(Poly b) { return (*this) = (*this) * b; }
  Poly deriv() const {
    if (a.empty()) return Poly();
    std::vector<Z> res(size() - 1);
    for (int i = 0; i < size() - 1; ++i) res[i] = (i + 1) * a[i + 1];
    return Poly(res);
  }
  Poly integr() const {
    std::vector<Z> res(size() + 1);
    for (int i = 0; i < size(); ++i) res[i + 1] = a[i] / (i + 1);
    return Poly(res);
  }
  Poly inv(int m) const {
    Poly x{a[0].inv()};
    int k = 1;
    while (k < m) k *= 2, x = (x * (Poly{2} - modxk(k) * x)).modxk(k);
    return x.modxk(m);
  }
  Poly log(int m) const {
    return (deriv() * inv(m)).integr().modxk(m);
  }
  Poly exp(int m) const {
    Poly x{1};
    int k = 1;
    while (k < m) k *= 2, x = (x * (Poly{1} - x.log(k) + modxk(k))).modxk(k);
    return x.modxk(m);
  }
  Poly sqrt(int m) const {
    Poly x{1};
    int k = 1;
    while (k < m) k *= 2, x = (x + (modxk(k) * x.inv(k)).modxk(k)) * ((P + 1) / 2);
    return x.modxk(m);
  }
  Poly mulT(Poly b) const {
    if (b.size() == 0) return Poly();
    int n = b.size();
    std::reverse(b.a.begin(), b.a.end());
    return ((*this) * b).divxk(n - 1);
  }
  std::vector<Z> eval(std::vector<Z> x) const {
    if (size() == 0) return std::vector<Z>(x.size(), 0);
    const int n = std::max(int(x.size()), size());
    std::vector<Poly> q(4 * n);
    std::vector<Z> ans(x.size());
    x.resize(n);
    std::function<void(int, int, int)> build = [&](int p, int l, int r) {
      if (r - l == 1) q[p] = Poly{1, -x[l]};
      else {
        int m = (l + r) / 2;
        build(2 * p, l, m), build(2 * p + 1, m, r);
        q[p] = q[2 * p] * q[2 * p + 1];
      }
    };
    build(1, 0, n);
    std::function<void(int, int, int, const Poly &)> work = [&](int p, int l, int r, const Poly &num) {
    if (r - l == 1) {
      if (l < int(ans.size())) ans[l] = num[0];
    } else {
      int m = (l + r) / 2;
      work(2 * p, l, m, num.mulT(q[2 * p + 1]).modxk(m - l));
      work(2 * p + 1, m, r, num.mulT(q[2 * p]).modxk(r - m));
    }
    };
    work(1, 0, n, mulT(q[1].inv(n)));
    return ans;
  }
};
}

using namespace Poly_space;

const int maxn = 200010;

int n, a[maxn], dep[maxn], sz[maxn], b[maxn], up[maxn], tot;
Poly F[maxn];
Z f[maxn], g[maxn], h[maxn];
char s[maxn];
pii ed[maxn];
vector<int> e[maxn];

void dfs(int u, int fa) {
  dep[u] = dep[fa] + 1, sz[u] = a[u];
  for (int v : e[u]) {
    if (v == fa) continue;
    dfs(v, u), sz[u] += sz[v];
  }
}

Poly fz(int l, int r) {
  if (l == r) return F[l];
  int mid = (l + r) >> 1;
  return fz(l, mid) * fz(mid + 1, r);
}

void solve(int u, int fa) {
  for (int v : e[u]) {
    if (v == fa) continue;
    solve(v, u);
  }
  tot = 0;
  for (int v : e[u]) {
    if (v == fa) continue;
    tot++, F[tot].a.clear();
    F[tot].a.emplace_back(f[v]);
    F[tot].a.emplace_back(g[v]);
    F[tot].a.emplace_back(h[v]);
  }
  tot++;
  F[tot].a.clear();
  if (a[u]) {
    F[tot].a.emplace_back(1);
    F[tot].a.emplace_back(1);
    F[tot].a.emplace_back(0);
  } else {
    F[tot].a.emplace_back(0);
    F[tot].a.emplace_back(1);
    F[tot].a.emplace_back(1);
  }
  Poly res = fz(1, tot);
  f[u] = res.a[tot - 1], g[u] = res.a[tot], h[u] = res.a[tot + 1];
  if (up[u]) h[u] = 0;
  else f[u] = 0;
}

int main() {
  cin.tie(nullptr) -> ios::sync_with_stdio(false);
  cin >> n >> s;
  rep (i, 1, n) a[i] = (s[i - 1] == 'S');
  rep (i, 1, n - 1) {
    int u, v;
    cin >> u >> v;
    ed[i] = pii(u, v);
    e[u].emplace_back(v);
    e[v].emplace_back(u);
  }
  dfs(1, 0);
  rep (i, 1, n - 1) {
    auto [u, v] = ed[i];
    if (dep[u] < dep[v]) up[v] = 0;
    else up[u] = 1;
  }
  solve(1, 0);
  cout << g[1].val() << '\n';
}