#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:102400000,102400000")
using namespace std;
template <class U, class T>
void Max(U &first, T second) {
  if (first < second) first = second;
}
template <class U, class T>
void Min(U &first, T second) {
  if (first > second) first = second;
}
template <class T>
void add(int &a, T b) {
  a = (a + b) % 998244353;
}
inline int gcd(int a, int b) { return b == 0 ? a : gcd(b, a % b); }
inline long long gcd(long long a, long long b) {
  return b == 0 ? a : gcd(b, a % b);
}
int pow(int a, int b) {
  int ans = 1;
  while (b) {
    if (b & 1) ans = 1LL * ans * a % 998244353;
    a = 1LL * a * a % 998244353;
    b >>= 1;
  }
  return ans;
}
int pow(int a, int b, int c) {
  int ans = 1;
  while (b) {
    if (b & 1) ans = 1LL * ans * a % c;
    a = 1LL * a * a % c;
    b >>= 1;
  }
  return ans;
}
vector<int> g[300010];
int d[300010], p[300010][19], st[300010], ed[300010], cnt, a[300010];
void dfs(int u, int fa = -1) {
  st[u] = cnt++;
  for (auto &v : g[u]) {
    if (v == fa) continue;
    d[v] = d[u] + 1;
    p[v][0] = u;
    for (int i = 1; i < 19; i++) p[v][i] = p[p[v][i - 1]][i - 1];
    dfs(v, u);
  }
  ed[u] = cnt;
}
bool cmp(int a, int b) { return st[a] < st[b]; }
int Ans(int a, int b) { return st[a] <= st[b] && ed[a] >= ed[b]; }
int lca(int a, int b) {
  if (d[a] < d[b]) swap(a, b);
  int h = d[a] - d[b];
  for (int i = 19 - 1; i >= 0; i--)
    if (h >> i & 1) a = p[a][i];
  if (a == b) return a;
  for (int i = 19 - 1; i >= 0; i--)
    if (p[a][i] != p[b][i]) a = p[a][i], b = p[b][i];
  return p[a][0];
}
int go(int u, int rt, int co) {
  if (a[rt] == 0)
    a[rt] = co;
  else if (a[rt] != co)
    return 0;
  while (u != rt) {
    if (a[u] == 0)
      a[u] = co;
    else if (a[u] != co)
      return 0;
    u = p[u][0];
  }
  return 1;
}
int vis[300010], sz, e[300010], f[300010], dp[300010][2];
void dfs1(int u, int fa = -1) {
  if (a[u]) {
    dp[u][1] = 0;
    dp[u][0] = 1;
    return;
  }
  dp[u][1] = 1;
  for (auto &v : g[u]) {
    if (vis[v] || v == fa) continue;
    dfs1(v, u);
    f[v] = (dp[v][1] + dp[v][0]) % 998244353;
    dp[u][1] = 1LL * dp[u][1] * f[v] % 998244353;
  }
  for (auto &v : g[u]) {
    if (vis[v] || v == fa) continue;
    add(dp[u][0], 1LL * dp[u][1] * pow(f[v], 998244353 - 2) % 998244353 *
                      dp[v][0] % 998244353);
  }
  a[u] = 1;
}
vector<int> q[300010];
int main() {
  int T, ca = 0, k, i, j, m = 0, K, n;
  scanf("%d%d", &n, &K);
  for (int i = 0; i < n; i++) {
    scanf("%d", &k);
    if (k) q[k].push_back(i);
    a[i] = k;
  }
  for (int i = 1; i < n; i++) {
    scanf("%d%d", &j, &k);
    j--, k--;
    g[j].push_back(k), g[k].push_back(j);
  }
  dfs(0);
  for (int i = 1; i < K + 1; i++)
    if ((int)q[i].size() > 1) {
      int rt = q[i][0];
      for (int j = 1; j < (int)q[i].size(); j++) {
        rt = lca(q[i][j], rt);
      }
      for (auto &second : q[i]) {
        int first = second;
        while (first != rt) {
          first = p[first][0];
          if (a[first] == i) break;
          if (a[first] == 0) a[first] = i;
          if (a[first] != i) {
            puts("0");
            return 0;
          }
        }
      }
    }
  queue<int> qu;
  for (int i = 0; i < n; i++) d[i] = (int)g[i].size();
  for (int i = 0; i < n; i++)
    if (a[i] == 0 && d[i] == 1) {
      qu.push(i);
      vis[i] = 1;
    }
  while (!qu.empty()) {
    int u = qu.front();
    qu.pop();
    for (auto &v : g[u]) {
      if (a[v] || vis[v]) continue;
      d[v]--;
      if (d[v] == 1) vis[v] = 1, qu.push(v);
    }
  }
  int ans = 1;
  for (int i = 0; i < n; i++)
    if (a[i] == 0 && !vis[i]) {
      dfs1(i);
      ans = 1LL * ans * dp[i][0] % 998244353;
    }
  printf("%d\n", ans);
}
