#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll INF = 1e9+7;
const ll MOD = 998244353;
typedef pair<ll,ll> ii;
#define iii pair<ll,ii>
#define f(i,a,b) for(ll i = a;i < b;i++)
#define pb push_back
#define vll vector<ll>
#define F first
#define S second
#define all(x) (x).begin(), (x).end()
///I hope I will get uprating and don't make mistakes
///I will never stop programming
///sqrt(-1) Love C++
///Please don't hack me
///@TheofanisOrfanou Theo830
///Think different approaches (bs,dp,greedy,graphs,shortest paths,mst)
///Stay Calm
///Look for special cases
///Beware of overflow and array bounds
///Think the problem backwards
///Training
ll n;
ll p[200005];
vector<vll>adj;
ll dp[200005];
ll solve(ll idx){
if(dp[idx] != -1){
return dp[idx];
}
ll ans = 0;
queue<ll>q;
ll dist[n+5];
memset(dist,-1,sizeof dist);
dist[idx] = 0;
q.push(idx);
while(!q.empty()){
ll f = q.front();
q.pop();
for(auto x:adj[f]){
if(dist[x] == -1 && p[x] < p[idx]){
q.push(x);
dist[x] = dist[f] + 1;
ans = max(ans,dist[x] + solve(x));
}
}
}
return dp[idx] = ans;
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cin>>n;
adj.assign(n+5,vll());
ll root = -1;
f(i,0,n){
cin>>p[i+1];
if(p[i+1] == n){
root = i+1;
}
}
f(i,0,n-1){
ll a,b;
cin>>a>>b;
adj[a].pb(b);
adj[b].pb(a);
}
memset(dp,-1,sizeof dp);
cout<<solve(root)<<"\n";
}
