#include <bits/stdc++.h>
using namespace std;
const int maxn = 2e5 + 100;
bool mark[maxn];
vector <int> poec[maxn], ne[maxn], nb;
int p[maxn], c[maxn];
bool s[maxn], block[maxn];
int nos[maxn], vu[maxn];
int find(int v, int k)
{
nos[c[v]] = 0;
s[c[v]] = 0;
mark[v] = 1;
bool ok = 1;
vu[v] = 1;
int ret = -1;
for (auto u : ne[v])
{
if (mark[u])
{
continue;
}
p[u] = v;
ret = max(ret, find(u, k));
vu[v] += vu[u];
ok &= (vu[u] <= k / 2);
}
if (ok and vu[v] >= (k + 1) / 2)
{
ret = v;
}
mark[v] = 0;
return ret;
}
void dfs(int v, bool op)
{
mark[v] = 1;
if (s[c[v]] == 0 and op)
{
nos[c[v]]++;
}
s[c[v]] = op;
for (auto u : ne[v])
{
if (mark[u])
{
continue;
}
dfs(u, op);
}
mark[v] = 0;
return ;
}
void check(int v)
{
if (nos[c[v]] > 1 and block[c[v]] == 0)
{
nb.push_back(c[v]);
}
mark[v] = 1;
for (auto u : ne[v])
{
if (mark[u])
{
continue;
}
check(u);
}
mark[v] = 0;
return ;
}
int solve(int v, int sz)
{
if (sz == 1)
{
if (block[c[v]])
{
return maxn;
}
return 0;
}
v = find(v, sz);
p[v] = 0;
find(v, 0);
queue <int> q, qq;
s[c[v]] = 1;
int ans = 0;
if (block[c[v]])
{
ans = maxn;
}
else
{
for (auto o : poec[c[v]])
{
q.push(o);
}
}
while (q.size())
{
int v = q.front();
while (v and mark[v] == 0)
{
mark[v] = 1;
qq.push(v);
qq.push(v);
if (!s[c[v]])
{
if (block[c[v]])
{
ans = maxn;
}
else
{
ans++;
s[c[v]] = 1;
for (auto o : poec[c[v]])
{
q.push(o);
}
}
}
v = p[v];
}
q.pop();
}
while (qq.size())
{
int o = qq.front();
mark[o] = 0;
s[c[o]] = 0;
qq.pop();
}
mark[v] = 1;
nos[c[v]] = 2;
for (auto u : ne[v])
{
if (mark[u])
{
continue;
}
dfs(u, 1);
dfs(u, 0);
}
check(v);
mark[v] = 1;
vector <int> tmp = nb;
nb.clear();
for (auto o : tmp)
{
block[o] = 1;
}
for (auto u : ne[v])
{
if (mark[u])
{
continue;
}
ans = min(ans, solve(u, vu[u]));
}
for (auto o : tmp)
{
block[o] = 0;
}
return ans;
}
int main()
{
int n, k;
cin >> n >> k;
for (int i = 1;i < n;i++)
{
int v, u;
cin >> v >> u;
ne[v].push_back(u);
ne[u].push_back(v);
}
for (int i = 1;i <= n;i++)
{
cin >> c[i];
poec[c[i]].push_back(i);
}
cout << solve(1, n);
}
