#include<bits/stdc++.h>
using namespace std;
#define task "a"
#define se second
#define fi first
#define ll long long
#define ii pair<ll, ll>
const long mxN = 5e5 + 7;
int par[mxN][25], n, h[mxN], dp[mxN], m, dsu[mxN], cnt[mxN];
bool vis[mxN];
vector<int> vc[mxN], w[mxN];
void Build(int j)
{
for (int i = 1; i <= 19; i++)
par[j][i] = par[par[j][i - 1]][i - 1];
for (int i : w[j])
{
if (h[i])
continue;
h[i] = h[j] + 1;
par[i][0] = j;
Build(i);
}
}
int LCA(int u, int v)
{
if (h[u] < h[v])
swap(u, v);
for (int i = 20; i >= 0; i--)
{
if (h[par[u][i]] >= h[v])
u = par[u][i];
}
if (u == v)
return u;
for (int i = 20; i >= 0; i--)
{
if (par[u][i] != par[v][i])
{
u = par[u][i];
v = par[v][i];
}
}
return par[u][0];
}
int Find(int j)
{
if (dsu[j] == j)
return j;
else
return dsu[j] = Find(dsu[j]);
}
void Union(int u, int v)
{
u = Find(u);
v = Find(v);
dsu[u] = v;
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
//freopen(task".INP", "r", stdin);
//freopen(task".OUT", "w", stdout);
cin >> n >> m;
for (int i = 1; i < n; i++)
{
int u, v;
cin >> u >> v;
w[u].push_back(v);
w[v].push_back(u);
}
h[1] = 1;
Build(1);
for (int i = 1; i <= n; i++)
{
int tmp;
cin >> tmp;
vc[tmp].push_back(i);
dsu[i] = i;
}
Union(1, 0);
for (int i = 1; i <= m; i++)
{
int root = vc[i][0];
for (int j : vc[i])
root = LCA(root, j);
for (int j : vc[i])
{
while (1)
{
j = Find(j);
if (h[j] <= h[root])
break;
Union(j, par[j][0]);
}
}
}
for (int i = 1; i <= n; i++)
{
for (int j : w[i])
{
if (Find(i) != Find(j))
cnt[Find(i)]++;
}
}
int ans = 0;
for (int i = 1; i <= n; i++)
ans += (cnt[i] == 1);
cout << (ans + 1) / 2;
}
