/**
____ ____ ____ ____ ____ ____
||l |||e |||i |||n |||a |||d ||
||__|||__|||__|||__|||__|||__||
|/__\|/__\|/__\|/__\|/__\|/__\|
**/
#include<bits/stdc++.h>
#define endl '\n'
using namespace std;
typedef long long ll;
void speed()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
}
const int maxn = 2e5 + 10;
int n, k, c[maxn];
vector < int > adj[maxn];
vector < int > col[maxn];
void input()
{
cin >> n >> k;
for (int i = 1; i < n; i ++)
{
int v, u;
cin >> v >> u;
///cout << "edge " << v << " " << u << endl;
adj[v].push_back(u);
adj[u].push_back(v);
}
for (int i = 1; i <= n; i ++)
cin >> c[i], col[c[i]].push_back(i);
}
int sub[maxn], par[maxn], last[maxn], used[maxn];
int timer;
void calc(int v, int p)
{
//cout << "calc " << v << " " << p << endl;
last[v] = timer;
par[v] = p;
sub[v] = 1;
for (int u : adj[v])
{
//cout << "neib " << v << " " << u << endl;
if (used[u] || u == p)
continue;
calc(u, v);
sub[v] += sub[u];
}
}
int find_centroid(int v, int p, int sz)
{
for (int u : adj[v])
{
if (u == p || used[u])
continue;
if (sub[u] >= sz / 2)
return find_centroid(u, v, sz);
}
return v;
}
int ans, mark[maxn];
void make_tree(int v)
{
/**cout << "make tree" << endl;
for (int i = 1; i <= n; i ++)
cout << last[i] << " ";
cout << endl;*/
vector < int > cs;
/**for (int i = 1; i <= k; i ++)
mark[i] = 0;*/
queue < int > q;
for (int cur : col[c[v]])
{
if (last[cur] != timer)
return;
q.push(cur);
}
mark[c[v]] = 1;
cs.push_back(c[v]);
int cnt = 0;
while(!q.empty())
{
int cur = q.front();
q.pop();
///cout << "queue " << cur << endl;
if (par[cur] != -1 && !mark[c[par[cur]]])
{
cnt ++;
mark[c[par[cur]]] = 1;
cs.push_back(c[par[cur]]);
for (int ver : col[c[par[cur]]])
{
if (last[ver] != timer)
{
for (int ps : cs)
mark[ps] = 0;
return;
}
q.push(ver);
}
}
}
///cout << cnt << endl;
ans = min(ans, cnt);
for (int ps : cs)
mark[ps] = 0;
///exit(0);
}
void decompose(int v)
{
timer ++;
calc(v, -1);
int centroid = find_centroid(v, -1, sub[v]);
///cout << "centroid " << v << endl;
make_tree(centroid);
used[centroid] = 1;
for (int u : adj[centroid])
{
if (!used[u])
decompose(u);
}
}
void solve()
{
input();
ans = n;
decompose(1);
cout << ans << endl;
}
int main()
{
speed();
solve();
return 0;
}
