#include<bits/stdc++.h>
using namespace std;
const int N = 5e5 + 1;
vector<int> g[N];
vector<int> a[N];
vector<int> s[N];
int st[N], en[N];
int tot = 0;
int f[N];
int h[N];
int p[N][20];
int dfs(int u) {
st[u] = ++tot;
for(int i = 0 ; i < 18 ; ++i)
p[u][i + 1] = p[p[u][i]][i];
for(int v : g[u]) if (v != p[u][0]) {
h[v] = h[u] + 1;
p[v][0] = u;
dfs(v);
}
en[u] = tot;
return 1;
}
int par(int u,int d) {
for(int i = 0 ; i < 19 ; ++i) if (d >> i & 1)
u = p[u][i];
return u;
}
int lca(int u,int v) {
if (h[u] < h[v])
swap(u,v);
u = par(u,h[u] - h[v]);
if (u == v) return u;
for(int i = 18 ; i >= 0 ; --i) if (p[u][i] != p[v][i]) {
u = p[u][i];
v = p[v][i];
}
return p[u][0];
}
int upd(int u) {
for(int v : g[u]) if (v != p[u][0])
upd(v), f[u] += f[v];
return 1;
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
int n; cin >> n;
int k; cin >> k;
for(int i = 2 ; i <= n ; ++i) {
int x; cin >> x;
int y; cin >> y;
g[x].push_back(y);
g[y].push_back(x);
}
for(int i = 1 ; i <= n ; ++i) {
int x; cin >> x;
s[x].push_back(i);
}
dfs(1);
auto cmp = [&](int x,int y) {
return st[x] < st[y];
};
auto con = [&](vector<int> v,int x,int y) {
sort(v.begin(),v.end(),cmp); v.erase(unique(v.begin(),v.end()),v.end());
for(int j = 1, K = v.size() ; j < K ; ++j)
v.push_back(lca(v[j - 1],v[j]));
sort(v.begin(),v.end(),cmp); v.erase(unique(v.begin(),v.end()),v.end());
stack<int> T;
for(int a : v) {
for(; T.size() && en[T.top()] < en[a] ; T.pop());
if (T.size())
f[T.top()] += x,
f[a] += y;
T.push(a);
}
};
for(int i = 1 ; i <= k ; ++i) con(s[i],-1,1);
upd(1);
vector<int> vec;
for(int i = 2 ; i <= n ; ++i) if(!f[i])
vec.push_back(i),
vec.push_back(p[i][0]);
memset(f,0,sizeof f);
con(vec,1,1);
int cnt = 0;
for(int i = 1 ; i <= n ; ++i) if (f[i] == 1)
cnt++;
cout << (cnt + 1) / 2 << endl;
}
