#include <bits/stdc++.h>
using namespace std;
#define dbg(x) cerr << #x << ": " << x << endl;
const int MAX_N = 2e5 + 5;
const int MAX_K = 20;
vector<int> g[MAX_N];
int tin[MAX_N];
int tout[MAX_N];
int timer = 0;
int binup[MAX_K][MAX_N];
int depth[MAX_N];
int parent[MAX_N];
int find(int v) {
if (parent[v] == v) {
return v;
} else {
return parent[v] = find(parent[v]);
}
}
void dfs(int v, int p) {
parent[v] = v;
tin[v] = timer++;
for (auto u : g[v]) {
if (u == p) continue;
binup[0][u] = v;
depth[u] = depth[v] + 1;
dfs(u, v);
}
tout[v] = timer++;
}
bool is_parent(int p, int v) {
return (tin[p] <= tin[v] && tout[v] <= tout[p]);
}
int lca(int u, int v) {
if (is_parent(u, v)) return u;
if (is_parent(v, u)) return v;
for (int k = MAX_K - 1; k >= 0; --k) {
if (!is_parent(binup[k][v], u)) {
v = binup[k][v];
}
}
return binup[0][v];
}
int dist(int u, int v) {
return depth[u] + depth[v] - 2 * depth[lca(u, v)];
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int n;
cin >> n;
vector<int> p(n);
for (auto& x : p) {
cin >> x;
--x;
}
for (int i = 0; i < n - 1; ++i) {
int u, v;
cin >> u >> v;
--u, --v;
u = p[u];
v = p[v];
g[u].push_back(v);
g[v].push_back(u);
}
dfs(0, -1);
for (int k = 1; k < MAX_K; ++k) {
for (int v = 0; v < n; ++v) {
binup[k][v] = binup[k - 1][binup[k - 1][v]];
}
}
vector<int64_t> dp(n);
for (int v = 0; v < n; ++v) {
for (auto u : g[v]) {
u = find(u);
if (u < v) {
parent[u] = v;
dp[v] = max(dp[v], dp[u] + dist(u, v));
}
}
}
cout << dp.back() << '\n';
return 0;
}
