#include <bits/stdc++.h>
using namespace std;
const int P = 998244353, INF = 0x3f3f3f3f;
long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }
long long qpow(long long a, long long n) {
  long long r = 1 % P;
  for (a %= P; n; a = a * a % P, n >>= 1)
    if (n & 1) r = r * a % P;
  return r;
}
long long inv(long long first) {
  return first <= 1 ? 1 : inv(P % first) * (P - P / first) % P;
}
const int N = 1e6 + 10;
int n, k;
vector<int> g[N], q;
int col[N], c[N], cnt[N];
int f[N][2], prod[N];
void dfs(int first, int fa) {
  cnt[first] = col[first] > 0;
  for (int second : g[first])
    if (second != fa) {
      dfs(second, first);
      if (!col[first])
        col[first] = col[second];
      else if (col[second] && col[first] != col[second]) {
        puts("0"), exit(0);
      }
      cnt[first] += cnt[second];
    }
  q.clear();
  for (int second : g[first])
    if (second != fa) q.push_back(second);
  prod[0] = 1;
  int sz = q.size();
  for (int i = 0; i <= sz - 1; ++i) {
    int second = q[i];
    prod[i + 1] = (long long)prod[i] * (f[second][0] + f[second][1]) % P;
  }
  if (col[first])
    f[first][1] = prod[sz];
  else {
    f[first][0] = prod[sz];
    int tmp = 1;
    for (int i = sz - 1; i >= 0; --i) {
      int second = q[i];
      f[first][1] =
          (f[first][1] + (long long)tmp * f[second][1] % P * prod[i] % P) % P;
      tmp = (long long)tmp * (f[second][0] + f[second][1]) % P;
    }
  }
  if (c[col[first]] == cnt[first]) cnt[first] = col[first] = 0;
}
int main() {
  scanf("%d%d", &n, &k);
  for (int i = 1; i <= n; ++i) scanf("%d", col + i);
  for (int i = 1; i <= n; ++i) ++c[col[i]];
  for (int i = 2; i <= n; ++i) {
    int u, v;
    scanf("%d%d", &u, &v);
    g[u].push_back(v), g[v].push_back(u);
  }
  dfs(1, 0);
  printf("%d\n", f[1][1]);
}
