//Author: Kevin5307
#include<bits/stdc++.h>
//#pragma GCC optimize("O2")
using namespace std;
#define ll long long
#define ull unsigned ll
#define pb push_back
#define mp make_pair
#define ALL(x) (x).begin(),(x).end()
#define rALL(x) (x).rbegin(),(x).rend()
#define srt(x) sort(ALL(x))
#define rev(x) reverse(ALL(x))
#define rsrt(x) sort(rALL(x))
#define sz(x) (int)(x.size())
#define inf 0x3f3f3f3f
#define pii pair<int,int>
#define lb(v,x) (int)(lower_bound(ALL(v),x)-v.begin())
#define ub(v,x) (int)(upper_bound(ALL(v),x)-v.begin())
#define uni(v) v.resize(unique(ALL(v))-v.begin())
#define longer __int128_t
void die(string S){puts(S.c_str());exit(0);}
namespace _kv_hash
{
	const ull mask=std::chrono::steady_clock::now().time_since_epoch().count();
	ull shift(ull x)
	{
		x^=mask;
		x^=x<<13;
		x^=x>>7;
		x^=x<<17;
		x^=mask;
		return x;
	}
}
using namespace _kv_hash;
const int maxn=200200;
vector<int> G[maxn];
int color[maxn];
bool flag[maxn];
vector<int> nodes;
int siz[maxn],mx[maxn];
int f[maxn];
void dfs2(int u,int fa)
{
	f[u]=fa;
	siz[u]=1;
	mx[u]=0;
	nodes.pb(u);
	for(auto v:G[u])
		if(v!=fa&&!flag[v])
		{
			dfs2(v,u);
			siz[u]+=siz[v];
			mx[u]=max(mx[u],siz[v]);
		}
}
int ans=inf;
vector<int> vec[maxn];
bool vis[maxn];
int cc[maxn];
void dfs(int root)
{
	nodes.clear();
	dfs2(root,0);
	for(auto u:nodes)
		mx[u]=max(mx[u],siz[root]-siz[u]);
	for(auto u:nodes)
		if(mx[u]<mx[root])
			root=u;
	for(auto u:nodes)
		vec[color[u]].pb(u);
	dfs2(root,0);
	bool fl=1;
	queue<int> q;
	int cnt=0;
	for(auto u:vec[color[root]])
	{
		vis[u]=1;
		q.push(u);
	}
	while(!q.empty())
	{
		int x=q.front();
		q.pop();
//		cerr<<x<<endl;
		if(cc[color[x]]!=sz(vec[color[x]]))
			fl=0;
		if(f[x]&&!vis[f[x]])
		{
			int p=f[x];
			cnt++;
			for(auto v:vec[color[p]])
			{
				vis[v]=1;
				q.push(v);
			}
		}
	}
//	cerr<<endl;
	if(fl)
		ans=min(ans,cnt);
	for(auto u:nodes)
	{
		vis[u]=0;
		vec[color[u]].clear();
	}
	flag[root]=1;
	for(auto v:G[root])
		if(!flag[v])
			dfs(v);
}
int main()
{
	int n,k;
	scanf("%d%d",&n,&k);
	for(int i=1;i<n;i++)
	{
		int u,v;
		scanf("%d%d",&u,&v);
		G[u].pb(v);
		G[v].pb(u);
	}
	for(int i=1;i<=n;i++)
	{
		scanf("%d",color+i);
		cc[color[i]]++;
	}
	dfs(1);
	printf("%d\n",ans);
	return 0;
}