#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
//#pragma GCC optimize("Ofast,unroll-loops")
//#pragma GCC target("avx2,popcnt,lzcnt,abm,bmi,bmi2,fma,tune=native")
#define all(x) x.begin(),x.end()
#define pb push_back
#define for1(i,x,n) for(int i=x;i<=n;i++)
#define for2(i,x,n) for(int i=x;i>=n;i--)
//#define int ll
typedef long long ll;
typedef pair<int,int> pii;
const ll maxn=2e5+13;
const ll mod=1e9+7;
const ll inf=1e18;
int n,k,c[maxn];
vector<int> adj[maxn],L[maxn];
int sz[maxn],par[maxn],cnt[maxn];
bool used[maxn],dd[maxn];
void dfs_sz(int u,int pre)
{
sz[u]=1;
cnt[c[u]]=0;
for(int v: adj[u])
{
if (v==pre||used[v]) continue;
dfs_sz(v,u);
sz[u]+=sz[v];
}
}
int Find_cen(int u,int pre,int ts)
{
for(int v:adj[u])
{
if (v==pre || used[v]) continue;
if (sz[v]*2>ts) return Find_cen(v,u,ts);
}
return u;
}
void dfs_on(int u,int pre)
{
par[u]=pre;
dd[c[u]]=0;
cnt[c[u]]++;
for(int v:adj[u])
{
if (v==pre||used[v]) continue;
dfs_on(v,u);
}
}
vector<int>Q;
int centroid(int u)
{
dfs_sz(u,-1);
u=Find_cen(u,-1,sz[u]);
used[u]=1;
dfs_on(u,-1);
Q.clear();
Q.pb(c[u]);
dd[c[u]]=1;
int res=0;
while (!Q.empty())
{
int cu=Q.back();
Q.pop_back();
if (cnt[cu]!=L[cu].size())
{
res=n;
break;
}
for(int v:L[cu])
{
if (par[v]==-1) continue;
if (!dd[c[par[v]]])
{
Q.pb(c[par[v]]);
dd[c[par[v]]]=1;
res++;
}
}
}
Q.clear();
// Q.clear();
// dfs_off(u,-1);
for(int v: adj[u]) if (!used[v]) res=min(res,centroid(v));
return res;
}
void sol()
{
cin >> n>>k;
for1(i,1,n-1)
{
int u,v; cin >> u>>v;
adj[u].pb(v);
adj[v].pb(u);
}
for1(i,1,n)
{
cin >>c[i];
L[c[i]].pb(i);
}
cout << centroid(1);
}
int32_t main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
// freopen("wall.inp","r",stdin);
// freopen("wall.out","w",stdout);
int t=1;//cin >> t;
while (t--)
{
// cerr<<"avdsava "<< t<<'\n';
sol();
}
}
/*
1
3
3 2 3 1 1 2
4 1
6 1
3 5
5 1
2 4
*/
