#include <bits/stdc++.h>
using namespace std;
vector<int> P, D, Max;
vector<bool> used;
vector<vector<int>> G;
void DFS(int u, int p) {
Max[u] = u;
for (int v : G[u]) {
if (v != p && !used[v]) {
D[v] = D[u] + 1;
DFS(v, u);
if (P[Max[v]] > P[Max[u]]) {
Max[u] = Max[v];
}
}
}
}
int solve(int u) {
D[u] = 0;
DFS(u, -1);
used[u] = true;
int ans = 0;
for (int v : G[u]) {
if (!used[v]) {
int dist = D[Max[v]];
ans = max(ans, dist + solve(Max[v]));
}
}
return ans;
}
int main() {
cin.tie(nullptr)->sync_with_stdio(false);
int N;
cin >> N;
P = D = Max = vector<int>(N);
G.resize(N);
used.resize(N);
for (int &v : P) {
cin >> v;
}
for (int i = 0; i < N - 1; i++) {
int u, v;
cin >> u >> v;
u--, v--;
G[u].push_back(v);
G[v].push_back(u);
}
for (int i = 0; i < N; i++) {
if (P[i] == N) {
cout << solve(i) << "\n";
}
}
}
