#include <bits/stdc++.h>
#define pb push_back
#define s second
#define f first
#define pb push_back
#define pii pair <int,int>
#define ll long long
#define int ll
using namespace std;
const int N = 3e5 + 5,inf = 1e18;
vector <pii> v[N],vec[N];
int col[N],tin[N],timer,d[25][N],dep[N];
int edge[N],val[N],n,D,I;
void dfs(int x,int par){
d[0][x] = par;
dep[x] = dep[par] + 1;
tin[x] = ++timer;
for (auto [to, id]: v[x]){
if (to != par) {
edge[to] = id;
dfs(to,x);
}
}
}
int lca(int x,int y){
if (dep[x] < dep[y ]) swap(x,y);
for (int i = 20; i >= 0; i--)
if (dep[d[i][x]] >= dep[y]) x = d[i][x];
if (x == y) return x;
for (int i = 20; i >= 0; i--)
if (d[i][x] != d[i][y]) x = d[i][x],y = d[i][y];
return d[0][x];
}
void getpath(int x,int y){
int c = lca(x,y);
while (x != c){
val[edge[x]] = 0;
x = d[0][x];
}
while (y != c){
val[edge[y]] = 0;
y = d[0][y];
}
}
void DFS(int x,int par,int dd){
if (dd >= D) D = dd,I = x;
for (auto [to,id]: v[x]){
if (to != par) DFS(to,x,dd + val[id]);
}
}
signed main() {
ios_base::sync_with_stdio(0),cin.tie(NULL),cout.tie(NULL);
int k;
cin>>n>>k;
for (int i = 1; i < n; i++){
int a,b;
cin>>a>>b;
v[a].pb({b,i});
v[b].pb({a,i});
val[i] = 1;
}
dfs(1,1);
for (int j = 1; j <= 20 ; j++)
for (int i = 1; i <= n; i++)
d[j][i] = d[j - 1][d[j - 1][i]];
for (int i = 1; i <= n; i++)
cin >> col[i],vec[col[i]].pb({tin[i],i});
for (int i = 1; i <= k; i++){
sort(vec[i].begin(),vec[i].end());
for (int j = 1; j < vec[i].size(); j++){
getpath(vec[i][j].s,vec[i][j - 1].s);
}
}
int sum = 0;
for (int i = 1; i < n; i++)
sum += val[i];
int ans = 0;
while (sum > 0){
++ans;
I = D = 0; DFS(1,1,0);
int x1 = I;
I = D = 0; DFS(x1,x1,0);
int y1 = I;
getpath(x1,y1);
sum -= D;
}
cout<<ans;
}
