#include <functional>
#include <algorithm>
#include <iostream>
#include <numeric>
#include <set>
#include <vector>
using u32 = uint32_t;
int main() {
u32 n, k;
std::cin >> n >> k;
std::vector<std::vector<u32>> g(n);
for (u32 i = 0; i < n - 1; ++i) {
u32 a, b;
std::cin >> a >> b;
--a, --b;
g[a].push_back(b);
g[b].push_back(a);
}
std::vector<std::vector<u32>> l(k);
for (u32 i = 0; i < n; ++i) {
u32 s;
std::cin >> s;
--s;
l[s].push_back(i);
}
std::vector<u32> d(n);
std::vector<u32> par(n);
std::function<void(u32, u32, u32)> const dfs = [&](u32 v, u32 p, u32 l) {
d[v] = l;
par[v] = p;
for (auto u : g[v])
if (u != p) dfs(u, v, l + 1);
};
dfs(0, 0, 0);
std::vector<u32> uf(n);
iota(uf.begin(), uf.end(), 0);
std::function<u32(u32)> const find = [&](u32 i) {
return uf[i] == i ? i : uf[i] = find(uf[i]);
};
auto const merge = [&](u32 i, u32 j) {
i = find(i);
j = find(j);
if (i == j) return;
if (d[i] > d[j]) std::swap(i, j);
uf[j] = i;
};
for (auto &m : l) {
std::set<std::pair<u32, u32>> s;
for (auto x : m) {
x = find(x);
s.emplace(d[x], x);
}
while (s.size() > 1) {
auto [_, v] = *s.rbegin();
s.erase(prev(s.end()));
merge(v, par[v]);
v = find(v);
s.emplace(d[v], v);
}
}
std::vector<u32> cnt(n);
for (u32 i = 1; i < n; ++i)
if (find(i) == i) {
auto j = find(par[i]);
cnt[i] += 1;
cnt[j] += 1;
}
auto x = count(cnt.begin(), cnt.end(), 1);
std::cout << (x + 1) / 2 << '\n';
}
