#include <bits/stdc++.h>
#define ll long long
#define ld double
#define pb push_back
#define pf push_front
#define ins insert
#define fr first
#define sc second
#define endl "\n"
#define ar array
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
using namespace std;
void start(){ios_base::sync_with_stdio(NULL);cin.tie(nullptr);cout.tie(nullptr);}
const ll inf = 1e17;
const ll mod = 1e9 + 7;
const ll N = 2e5 + 8;
vector<vector<ll>> g(N), ng(N);
ll siz[N], p[N], mx[N];
ll up[N][20], d[N];
ll anc(ll a){ return (p[a] == a ? a : anc(p[a])); }
bool uni(ll a, ll b){
a = anc(a), b = anc(b);
if(a == b) return false;
if(siz[a] > siz[b]) swap(a, b);
p[a] = b;
siz[b] += siz[a];
mx[b] = max(mx[a], mx[b]);
return true;
}
void dfs(ll v){
for(ll i=1;i<=19;i++) up[v][i] = up[up[v][i - 1]][i - 1];
for(auto i : g[v]){
if(i == up[v][0]) continue;
d[i] = d[v] + 1;
up[i][0] = v;
dfs(i);
}
}
ll lca(ll a, ll b){
if(d[a] < d[b]) swap(a, b);
for(ll i=19;i>=0;i--){
if(d[a] - d[b] >= (1<<i)){
a = up[a][i];
}
}
if(a == b) return a;
for(ll i=19;i>=0;i--){
if(up[a][i] != up[b][i]){
a = up[a][i];
b = up[b][i];
}
}
return up[a][0];
}
ll dis(ll a, ll b){
return d[a] + d[b] - 2 * d[lca(a, b)];
}
void solve() {
ll i, j;
ll n;
cin>>n;
ll v[n + 1];
for(i=1;i<=n;i++) {
cin>>v[i];
p[i] = i;
siz[i] = 1;
mx[i] = i;
}
for(i=1;i<n;i++){
ll a, b;
cin>>a>>b;
a = v[a];
b = v[b];
g[a].pb(b);
g[b].pb(a);
}
for(i=1;i<=n;i++){
for(auto to : g[i]){
if(to < i){
ng[i].pb(mx[anc(to)]);
//cout<<i<<' '<<mx[anc(to)]<<endl;
uni(i, to);
}
}
}
d[1] = 0;
up[1][0] = 1;
dfs(1);
vector<ll> ans(n + 1, 0);
ll mx = 0;
for(i=n;i>0;i--){
mx = max(mx, ans[i]);
//cout<<ans[i]<<endl;
for(auto to : ng[i]){
//cout<<i<<' '<<to<<' '<<dis(to, i)<<endl;
ans[to] = ans[i] + dis(to, i);
}
}
cout<<mx<<endl;
}
signed main(){
start();
ll t = 1;
//cin>>t;
while(t--) solve();
}
/*
*/
