#include <bits/stdc++.h>

using namespace std;

const int N = 5e5 + 10, M = 1e6 + 10, MOD = 998244353;
inline int Plus(int a, int b) {return a + b >= MOD ? a + b - MOD : a + b; }
inline int Minus(int a, int b) {return a - b < 0 ? a - b + MOD : a - b; }
int h[N], e[M], ne[M], idx;
inline void add(int a, int b) {e[idx] = b, ne[idx] = h[a], h[a] = idx ++; }
int n, k, A[N], val[N];
bool key[N];
int f[N][2];

void dfs(int u, int fa) {
    f[u][0] = 1;
    for(int i = h[u]; i != -1; i = ne[i]) {
        int v = e[i]; if(v == fa) continue;
        dfs(v, u);
        f[u][1] = Plus(1ll * f[u][1] * f[v][0] % MOD, 1ll * f[u][0] * f[v][1] % MOD);
        f[u][0] = 1ll * f[u][0] * f[v][0] % MOD;
    }
    if(key[u]) 
        f[u][1] = f[u][0], f[u][0] = 1ll * f[u][0] * Minus(val[u], val[fa]) % MOD;
    else 
        f[u][0] = Plus(f[u][0], 1ll * f[u][1] * Minus(val[u], val[fa]) % MOD);
}

int main() {
    ios::sync_with_stdio(false), cin.tie(0);
    memset(h, -1, sizeof h);

    cin >> n >> k;
    for(int i = 1; i <= n; i ++) cin >> val[i];
    for(int i = 1; i <= k; i ++) cin >> A[i];
    for(int i = 1; i <= k; i ++) key[A[i]] = true;
    for(int i = 1; i < n; i ++) {
        int a, b; cin >> a >> b;
        add(a, b), add(b, a);
    }
    dfs(1, 0);
    cout << f[1][0] << '\n';

    return 0;
}