#include <bits/stdc++.h>
using namespace std;
using ld = long double;
using ll = long long;
const int INF = 1e9, MOD = 1e9 + 7;
void solve();
signed main() {
#ifdef LOCAL
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
ios::sync_with_stdio(false);
cin.tie(0);
int q = 1;
while (q--) {
solve();
}
}
vector<vector<ll>> g;
void solve() {
ll n; cin >> n;
vector<ll> p(n), val(n);
for (int i = 0; i < n; i++) {
ll x; cin >> x; x--;
p[x] = i;
val[i] = x;
}
g.resize(n);
for (int i = 1; i < n; i++) {
ll a, b; cin >> a >> b;
a--, b--;
g[a].push_back(b);
g[b].push_back(a);
}
vector<ll> dp(n, -INF), cnt(n, -INF);
dp[n - 1] = 0;
for (auto v : g[p[n - 1]]) {
cnt[v] = 1;
}
for (ll i = n - 2; i >= 0; i--) {
queue<ll> bfs;
bfs.push(p[i]);
vector<ll> dist(n, -1);
dist[p[i]] = 0;
while (!empty(bfs)) {
ll v = bfs.front(); bfs.pop();
dp[i] = max(dp[i], cnt[v] + dist[v]);
for (auto u : g[v]) {
if (val[u] > i) continue;
if (dist[u] == -1) {
dist[u] = dist[v] + 1;
bfs.push(u);
}
}
}
for (auto v : g[p[i]]) {
cnt[v] = max(cnt[v], dp[i] + 1);
}
}
ll ans = 0;
for (int i = 0; i < n; i++) {
ans = max(ans, dp[i]);
}
cout << ans;
}
