#include <bits/stdc++.h>
using namespace std;
namespace io {
const int L = (1 << 20) + 1;
char buf[L], *S, *T, c;
char getchar() {
  if (__builtin_expect(S == T, 0)) {
    T = (S = buf) + fread(buf, 1, L, stdin);
    return (S == T ? EOF : *S++);
  }
  return *S++;
}
int inp() {
  int x = 0, f = 1;
  char ch;
  for (ch = getchar(); !isdigit(ch); ch = getchar())
    if (ch == '-') f = -1;
  for (; isdigit(ch); x = x * 10 + ch - '0', ch = getchar())
    ;
  return x * f;
}
unsigned inpu() {
  unsigned x = 0;
  char ch;
  for (ch = getchar(); !isdigit(ch); ch = getchar())
    ;
  for (; isdigit(ch); x = x * 10 + ch - '0', ch = getchar())
    ;
  return x;
}
long long inp_ll() {
  long long x = 0;
  int f = 1;
  char ch;
  for (ch = getchar(); !isdigit(ch); ch = getchar())
    if (ch == '-') f = -1;
  for (; isdigit(ch); x = x * 10 + ch - '0', ch = getchar())
    ;
  return x * f;
}
char B[25], *outs = B + 20, *outr = B + 20;
template <class T>
inline void print(register T a, register char x = 0) {
  if (x) *--outs = x, x = 0;
  if (!a)
    *--outs = '0';
  else
    while (a) *--outs = (a % 10) + 48, a /= 10;
  if (x) *--outs = x;
  fwrite(outs, outr - outs, 1, stdout);
  outs = outr;
}
};  // namespace io
using io ::inp;
using io ::inp_ll;
using io ::inpu;
using io ::print;
using i32 = int;
using i64 = long long;
using u8 = unsigned char;
using u32 = unsigned;
using u64 = unsigned long long;
using f64 = double;
using f80 = long double;
long long power(long long a, long long b, long long p) {
  if (!b) return 1;
  long long t = power(a, b / 2, p);
  t = t * t % p;
  if (b & 1) t = t * a % p;
  return t;
}
long long exgcd(long long a, long long b, long long &x, long long &y) {
  if (b == 0) {
    x = 1;
    y = 0;
    return a;
  }
  long long px, py;
  long long d = exgcd(b, a % b, px, py);
  x = py;
  y = px - a / b * py;
  return d;
}
template <class T>
inline void freshmin(T &a, const T &b) {
  if (a > b) a = b;
}
template <class T>
inline void freshmax(T &a, const T &b) {
  if (a < b) a = b;
}
const int MAXN = 300010;
const int MOD = 998244353;
const f80 MI = f80(1) / MOD;
const int INF = 1000000000;
int n, k;
vector<int> v[MAXN];
int a[MAXN], c[MAXN], to[MAXN];
int pre[MAXN];
int head, tail, Q[MAXN];
int u[MAXN];
vector<int> w[MAXN];
bool bfs() {
  Q[head = tail = 1] = u[1] = 1;
  while (head <= tail) {
    int x = Q[head++];
    for (auto y : v[x])
      if (!u[y]) {
        u[Q[++tail] = y] = 1;
        pre[y] = x;
      }
  }
  for (int k = n; k >= 1; --k) {
    int x = Q[k];
    if (!a[x]) continue;
    if (c[a[x]] == 1) {
      to[a[x]] = x;
      continue;
    }
    if (!a[pre[x]])
      a[pre[x]] = a[x];
    else if (a[pre[x]] == a[x])
      c[a[x]]--;
    else
      return false;
  }
  for (int x = 2; x <= n; ++x)
    if (!a[x] || a[x] != a[pre[x]]) {
      int y = pre[x];
      w[a[y] ? to[a[y]] : y].push_back(x);
    }
  return true;
}
int prod[MAXN];
int f[MAXN][2];
void dfs(int x) {
  for (auto y : w[x]) dfs(y);
  prod[w[x].size()] = 1;
  for (int i = w[x].size() - 1; i >= 0; --i) {
    int y = w[x][i];
    prod[i] = (long long)prod[i + 1] * (f[y][0] + f[y][1]) % MOD;
  }
  if (a[x] == 0) {
    f[x][0] = prod[0];
    f[x][1] = 0;
    for (int i = 0, tmp = 1; i < w[x].size(); ++i) {
      int y = w[x][i];
      f[x][1] = (f[x][1] + (long long)tmp * f[y][1] % MOD * prod[i + 1]) % MOD;
      tmp = (long long)tmp * (f[y][0] + f[y][1]) % MOD;
    }
  } else {
    f[x][0] = 0;
    f[x][1] = prod[0];
  }
}
int main() {
  n = inp();
  k = inp();
  for (int i = 1; i <= n; ++i) {
    a[i] = inp();
    c[a[i]]++;
  }
  for (int i = 1; i < n; ++i) {
    int x = inp();
    int y = inp();
    v[x].push_back(y);
    v[y].push_back(x);
  }
  if (!bfs()) {
    puts("0");
    return 0;
  }
  dfs(1);
  cout << f[1][1] << endl;
  return 0;
}
