# include <iostream>
# include <vector>
# include <algorithm>
# include <set>
# include <map>
# include <cmath>
using namespace std;
const int MAX=2e5+11;
int n,k;
vector<int> adj[MAX];
int col[MAX];
bool kill[MAX];
int sz[MAX];
int last[MAX];
bool add[MAX];
int cnt[MAX];
void dfs_sz(int curr, int par)
{
sz[curr]=1;
last[col[curr]]=0;
add[col[curr]]=0;
cnt[col[curr]]=0;
for(int nxt: adj[curr])
{
if(nxt==par or kill[nxt]) continue;
dfs_sz(nxt,curr);
sz[curr]+=sz[nxt];
}
}
int get_centroid(int curr, int par, int N)
{
for(int nxt: adj[curr])
{
if(nxt==par or kill[nxt]) continue;
if(sz[nxt]*2>N) return get_centroid(nxt,curr,N);
}
return curr;
}
void dfs_add(int curr, int par, int from)
{
if(last[col[curr]]!=from) add[col[curr]]=1;
last[col[curr]]=from;
for(int nxt: adj[curr])
{
if(nxt==par or kill[nxt]) continue;
dfs_add(nxt,curr,from);
}
}
int Limit;
set<int> s;
map<int, bool> colors[MAX];
bool over[MAX];
void dfs(int curr, int par)
{
cnt[col[curr]]++;
if(cnt[col[curr]]==1) s.insert(col[curr]);
if(!over[col[curr]])
{
if((int)s.size()>=Limit)
{
over[col[curr]]=1;
}
else
{
for(int x: s) colors[col[curr]][x]=1;
if((int)colors[col[curr]].size()>=Limit) over[col[curr]]=1;
}
}
for(int nxt: adj[curr])
{
if(nxt==par or kill[nxt]) continue;
dfs(nxt,curr);
}
cnt[col[curr]]--;
if(cnt[col[curr]]==0) s.erase(col[curr]);
}
void centroid_dc(int curr)
{
dfs_sz(curr,0);
curr=get_centroid(curr,0,sz[curr]);
last[col[curr]]=curr;
for(int nxt: adj[curr])
{
if(kill[nxt]) continue;
dfs_add(nxt,curr,nxt);
}
for(int nxt: adj[curr])
{
if(kill[nxt]) continue;
dfs(nxt,curr);
}
kill[curr]=1;
for(int nxt: adj[curr])
{
if(kill[nxt]) continue;
centroid_dc(nxt);
}
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
cin>>n>>k;
for(int i=1;i<n;i++)
{
int u,v;
cin>>u>>v;
adj[u].push_back(v);
adj[v].push_back(u);
}
for(int i=1;i<=n;i++) cin>>col[i];
Limit=sqrt(n)+3;
centroid_dc(1);
int ans=Limit;
for(int i=1;i<=k;i++)
{
if(over[i]) continue;
int curr_ans=colors[i].size();
if(colors[i].find(i)==colors[i].end()) curr_ans--;
ans=min(ans,curr_ans);
//cout<<i<<":"<<"\n";
//for(pair<int, bool> pa: colors[i]) cout<<pa.first<<" ";
//cout<<"\n";
}
cout<<ans<<"\n";
return 0;
}
