#include<bits/stdc++.h>
using namespace std;
#define task "a"
#define se second
#define fi first
#define ll long long
#define ii pair<ll, ll>
const long mxN = 2e5 + 7;
int h[mxN], par[mxN], in[mxN], n, k, arr[mxN], out[mxN], tree[mxN * 4], c[mxN], num, stt, root[mxN], ans, mn[mxN];
vector<int> w[mxN], path[mxN * 5];
void DFS(int j)
{
int mem = h[j] = h[par[j]] + 1;
for (int i : w[j])
{
if (h[i])
continue;
par[i] = j;
DFS(i);
mem = max(mem, h[i]);
}
h[j] = mem;
}
bool cmp(int u, int v)
{
return h[u] > h[v];
}
void TiTo(int j)
{
in[j] = ++num;
arr[num] = c[j];
sort(w[j].begin(), w[j].end(), cmp);
if (!stt)
stt = j;
root[j] = stt;
for (int i : w[j])
{
if (in[i])
continue;
TiTo(i);
}
stt = 0;
out[j] = num;
}
void Upd(int u, int v, int id, int j = 1, int l = 1, int r = n)
{
if (l > v || u > r)
return;
if (u <= l && r <= v)
{
path[id].push_back(j + k);
return;
}
int mid = (l + r) / 2;
Upd(u, v, id, j * 2, l, mid);
Upd(u, v, id, j * 2 + 1, mid + 1, r);
}
int LCA(int u, int v)
{
int tmp = c[v];
while (u != v)
{
if (in[u] > in[v])
swap(u, v);
if (root[u] == root[v])
{
Upd(in[u], in[v], tmp);
return u;
}
Upd(in[root[v]], in[v], tmp);
v = par[root[v]];
}
}
void Build(int j = 1, int l = 1, int r = n)
{
if (l == r)
{
path[j + k].push_back(arr[l]);
return;
}
int mid = (l + r) / 2;
path[j + k].push_back(j * 2 + k);
path[j + k].push_back(j * 2 + 1 + k);
Build(j * 2, l, mid);
Build(j * 2 + 1, mid + 1, r);
}
int low[mxN * 5], vis[mxN * 5];
bool tt[mxN * 5];
vector<int> vc;
void Tarzan(int j)
{
int tmp = low[j] = ++num;
vis[j] = 1;
tt[j] = 1;
vc.push_back(j);
for (int i : path[j])
{
if (!vis[i])
Tarzan(i);
if (vis[i] == 1)
low[j] = min(low[i], low[j]);
tt[j] &= tt[i];
}
if (low[j] != tmp)
return;
bool lf = tt[j];
int cntt = 0;
while (vis[j] == 1)
{
vis[vc.back()] = 2;
tt[vc.back()] = 0;
cntt += (vc.back() <= k);
vc.pop_back();
}
if (lf)
ans = min(ans, cntt - 1);
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
//freopen(task".INP", "r", stdin);
//freopen(task".OUT", "w", stdout);
cin >> n >> k;
for (int i = 1; i < n; i++)
{
int u, v;
cin >> u >> v;
w[u].push_back(v);
w[v].push_back(u);
}
for (int i = 1; i <= n; i++)
cin >> c[i];
DFS(1);
TiTo(1);
Build(1);
for (int i = 1; i <= n; i++)
{
if (mn[c[i]])
mn[c[i]] = LCA(mn[c[i]], i);
else
mn[c[i]] = i;
}
// for (int i = 1; i <= n * 3; i++)
// {
// cout << i << " : ";
// for (int j : path[i])
// cout << j << " ";
// cout << '\n';
// }
ans = n;
for (int i = 1; i <= k; i++)
{
if (!vis[i])
Tarzan(i);
}
cout << ans;
}
