#include<bits/stdc++.h>
#define pb push_back
#define mp make_pair
#define int long long
#define vi vector<int>
#define vvi vector<vector<int>>
#define pii pair<int, int>
#define vpii vector<pair<int, int>>
#define vc vector<char>
#define vb vector<bool>
#define mii map<int,int>
#define f0r(i,n) for(int i=0;i<n;i++)
#define FOR(i,k,n) for(int i=k;i<n;i++)
#define all(v) (v).begin(),(v).end()
#define rall(v) (v).rbegin(),(v).rend()
#define in(a) int a; cin>>a
#define in2(a,b) int a,b; cin>>a>>b
#define in3(a,b,c) int a,b,c; cin>>a>>b>>c
#define in4(a,b,c,d) int a,b,c,d; cin>>a>>b>>c>>d
#define vin(v,n); vi v(n); f0r(i,n){cin>>v[i];}
#define out(a) cout<<a<<'\n'
#define out2(a,b) cout<<a<<' '<<b<<'\n'
#define out3(a,b,c) cout<<a<<' '<<b<<' '<<c<<'\n'
#define out4(a,b,c,d) cout<<a<<' '<<b<<' '<<c<<' '<<d<<'\n'
#define pout(a) cout<<a.first<<' '<<a.second<<'\n'
#define vout(v) for(auto u : v){cout<<u<<' ';} cout<<'\n'
#define dout(a) cout<<a<<' '<<#a<<'\n'
#define dout2(a,b) cout<<a<<' '<<#a<<' '<<b<<' '<<#b<<'\n'
#define yn(x); if(x){cout<<"YES"<<'\n';}else{cout<<"NO"<<'\n';}
const int leg = 1e9 + 7;
const int mod = 998244353;
using namespace std;
signed main(){
ios::sync_with_stdio(false);
cin.tie(NULL);
//ifstream cin(".in");
//ofstream cout(".out");
in(n);
vin(v,n);
vvi adj(n);
f0r(i,n-1){
in2(a,b);
a--; b--;
adj[a].pb(b);
adj[b].pb(a);
}
vi numtonode(n);
f0r(i,n){
numtonode[v[i] - 1] = i;
}
vector<vpii> nxt(n);
for(int i = n-1; i>=0; i--){
int cur = numtonode[i];
queue<pii>q;
vi dep(n, -4e18);
vb vis(n);
dep[cur] = 0;
q.push(mp(cur,-1));
vis[cur] = 1;
for(int j = i+1; j<n; j++){
vis[numtonode[j]] = 1;
}
// vout(vis);
while(!q.empty()){
int node = q.front().first;
int lo = q.front().second;
q.pop();
for(auto u : adj[node]){
if(!vis[u]){
if(v[u] > lo){
q.push(mp(u, v[u]));
dep[u] = dep[node] + 1;
vis[u] = 1;
nxt[i].pb(mp(v[u]-1, dep[u]));
}
else{
q.push(mp(u, lo));
dep[u] = dep[node] + 1;
vis[u] = 1;
}
}
}
}
// vout(dep);
}
vi dp(n);
dp[n-1] = 0;
for(int i = n-1; i>=0; i--){
// dout(i);
for(pii x : nxt[i]){
// pout(x);
dp[x.first] = max(dp[x.first], dp[i] + x.second);
}
// cout<<'\n';
}
out(*max_element(all(dp)));
}
