#include <bits/stdc++.h>
using namespace std;
const int mxN=5e5;
int n, k, tin[mxN], low[mxN], dt, ci, d[mxN], ans, who[mxN], st[2*mxN], sth;
vector<array<int, 2>> adj[mxN];
vector<int> bs[mxN];
void dfs1(int u=0, int p=-1) {
tin[u]=dt++;
for(array<int, 2> v : adj[u])
if(v[1]^p)
dfs1(v[0], v[1]);
}
void dfs2(int u=0, int p=-1) {
tin[u]=low[u]=dt++;
st[sth++]=u;
for(array<int, 2> v : adj[u]) {
if(v[1]==p)
continue;
if(!tin[v[0]]) {
dfs2(v[0], v[1]);
low[u]=min(low[v[0]], low[u]);
} else
low[u]=min(tin[v[0]], low[u]);
}
if(low[u]==tin[u]) {
do
who[st[sth-1]]=ci;
while(st[--sth]^u);
++ci;
}
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cin >> n >> k;
for(int i=1, u, v; i<n; ++i) {
cin >> u >> v, --u, --v;
adj[u].push_back({v, i});
adj[v].push_back({u, i});
}
for(int i=0, si; i<n; ++i)
cin >> si, bs[si-1].push_back(i);
dfs1();
for(int i=0; i<k; ++i) {
sort(bs[i].begin(), bs[i].end(), [](int i, int j) {
return tin[i]<tin[j];
});
for(int j=0; j+1<bs[i].size(); ++j) {
adj[bs[i][j]].push_back({bs[i][j+1], dt});
adj[bs[i][j+1]].push_back({bs[i][j], dt++});
}
}
memset(tin, 0, 4*n);
dfs2();
for(int i=0; i<n; ++i)
for(array<int, 2> j : adj[i])
if(who[i]^who[j[0]])
++d[who[i]];
for(int i=0; i<ci; ++i)
ans+=d[i]==1;
cout << (ans+1)/2;
}
