#include<bits/stdc++.h>

using namespace std;
using E=long long;
constexpr E mod=998244353;

vector<int> vis,v,fa,sz;
vector<vector<int>> ver;
vector<vector<E>> dp;
E n,k;

void dfs(int u){
  dp[u][0]=1;
  if(vis[u]) sz[u]=1;
  for(auto p:ver[u]){
    if(p==fa[u]) continue;
    fa[p]=u;
    dfs(p);
    sz[u]+=sz[p];
  }
  dp[u][1]=(dp[u][1]+sz[u]*(v[u]-v[fa[u]]+mod))%mod;
  for(auto p:ver[u]){
    if(p==fa[u]) continue;
    for(int i=k; i>1; i--){
      E t=dp[p][i];
      for(int j=0; j<i-1; j++){
        t=(t+dp[u][i-j]*dp[p][j])%mod;
      }
      t=(t+(dp[u][1]-sz[p]*(v[u]-v[fa[u]]+mod)%mod+mod)*dp[p][i-1])%mod;
      dp[u][i]=t;
    }
    dp[u][1]=(dp[u][1]+dp[p][1])%mod;
  }
}

vector<int> dep,dfn;
int timestamp;
void dfs0(int u){
  dfn[u]=++timestamp;
  for(auto p:ver[u]){
    if(fa[u]==p) continue;
    fa[p]=u;
    dep[p]=dep[u]+1;
    dfs0(p);
  }
}

int lca(int x,int y){
  if(dep[x]<dep[y]) swap(x,y);
  while(dep[x]>dep[y]) x=fa[x];
  while(x!=y) x=fa[x],y=fa[y];
  return x;
}

int main(){

#ifdef zzafanti
  freopen("in.in","r",stdin);
#endif // zzafanti

  cin.tie(nullptr),cout.tie(nullptr)->sync_with_stdio(false);

  cin>>n>>k;
  dp=vector<vector<E>>(n+1,vector<E>(k+1));
  ver.resize(n+1);
  sz=dfn=dep=fa=vis=v=vector<int>(n+1);

  for(int i=1; i<=n; i++) cin>>v[i];
  for(int i=1; i<=k; i++){
    int a;
    cin>>a;
    vis[a]++;
  }
  for(int i=1; i<n; i++){
    int x,y;
    cin>>x>>y;
    ver[x].emplace_back(y);
    ver[y].emplace_back(x);
  }

  for(int i=1; i<=n; i++){
    if(vis[i]>1){
      cout<<0;
      return 0;
    }
  }

  dfs0(1);
  dfs(1);
  cout<<dp[1][k]<<endl;
  return 0;
  vector<int> A,B;
  for(int i=1; i<=n; i++){
    A.emplace_back(i);
    if(vis[i]) B.emplace_back(i);
  }

  sort(A.begin(),A.end(),[&](int x,int y){ return dfn[x]<dfn[y]; });
  sort(B.begin(),B.end(),[&](int x,int y){ return dfn[x]<dfn[y]; });

  cerr<<0<<' ';
  for(auto i:A) cerr<<i<<' ';
  cerr<<endl;
  for(auto i:B){
    cerr<<i<<' ';
    for(auto j:A){
      cerr<<(lca(i,j)==j)<<' ';
    }
    cerr<<endl;
  }

  return 0;
}