#include<bits/stdc++.h>
#define fr first
#define sc second
using namespace std;
void usaco(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
typedef long long ll;
#define USING_ORDERED_SET 0
#if USING_ORDERED_SET
#include<bits/extc++.h>
using namespace __gnu_pbds;
template<class T>using ordered_set=tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;
#endif
template<class T>void umax(T &a,T b){if(a<b)a=b;}
template<class T>void umin(T &a,T b){if(b<a)a=b;}
#ifdef IOI2021SG
#define printl(args...)printf(args)
#else
#define printl(args...)((void)0)
#endif
int n,k;
int tin[200005],tout[200005],timer,up[200005][18];
vector<int>g[200005],color[200005],g1[200005],g2[200005];
int a[200005];
void dfs(int v,int p){
tin[v]=++timer;
up[v][0]=p;
for(int i=1;i<18;i++)up[v][i]=up[up[v][i-1]][i-1];
for(int to:g[v])if(to!=p)dfs(to,v);
tout[v]=++timer;
}
bool upper(int a,int b){
return tin[a]<=tin[b]&&tout[a]>=tout[b];
}
int lca(int a,int b){
if(upper(a,b))return a;
if(upper(b,a))return b;
for(int i=17;i>=0;i--)if(!upper(up[a][i],b))a=up[a][i];
return up[a][0];
}
int lca(vector<int>&vec){
int l=vec[0];
for(int i=1;i<(int)vec.size();i++)l=lca(l,vec[i]);
return l;
}
unordered_map<int,bool>vs[200005];
vector<pair<int,int>>edges;
void add_edge(int a,int b){
if(a^b){
if(vs[a][b])return;
vs[a][b]=true;
edges.emplace_back(a,b);
g1[a].push_back(b);
}
}
void add(int v,int a,int l){
while(a!=l){
a=up[a][0];
add_edge(v,::a[a]);
if(v^::a[a])break;
}
}
int cnt=0;
bool vis[200005];
int low[200005],_up[200005],tt,last;
int sz[200005];
stack<int>ss;
int id[200005];
bool used[200005];
void run(int u,int p=-1){
low[u]=_up[u]=tt++;
used[u]=1;
ss.push(u);
for(auto x:g1[u])
if(used[x] && !id[x])umin(low[u],_up[x]);
else if(!id[x]) run(x,u),umin(low[u],low[x]);
if(low[u] == _up[u]){
int cur; ++last;
do{
cur = ss.top(); ss.pop();
id[cur] = last;
sz[last]++;
}while(cur != u);
}
}
int dp[200005];
int goo(int v){
if(~dp[v])return dp[v];
dp[v]=sz[v];
for(int to:g2[v])dp[v]+=goo(to);
return dp[v];
}
int main(){
memset(dp,-1,sizeof dp);
scanf("%d%d",&n,&k);
for(int i=1;i<n;i++){
int x,y;
scanf("%d%d",&x,&y);
g[x].push_back(y);
g[y].push_back(x);
}
for(int i=1;i<=n;i++){
scanf("%d",&a[i]);
color[a[i]].push_back(i);
}
dfs(1,1);
for(int i=1;i<=k;i++){
int l=lca(color[i]);
for(int j=0;j<(int)color[i].size();j++)add(i,color[i][j],l);
}
for(int i=1;i<=k;i++)if(!used[i])run(i);
for(auto to:edges)if(id[to.fr]^id[to.sc]){
g2[id[to.fr]].push_back(id[to.sc]);
}
int ans=k;
for(int i=1;i<=last;i++)umin(ans,goo(i));
printf("%d",ans-1);
}
