#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define ll long long
vector<int> q[200100];
int p[200100], sz[200100];
ll mx[200100];
ll dp[200100];
int jmp[200100][30];
int tin[200100], tout[200100], timer = 0;
int h[200100];
int pos[200100];
int a[200100];
int get(int a){
if(p[a] == a) return a;
return p[a] = get(p[a]);
}
void un(int x, int y){
x = get(x);
y = get(y);
if(x == y) return;
if(sz[x] > sz[y]) swap(x, y);
p[y] = p[x];
sz[x] += sz[y];
if(a[mx[x]] < a[mx[y]]) mx[x] = mx[y];
}
ll dfs(int v, int p, int k, int h){
ll res = dp[v] + k;
for(int to: q[v]){
if(to == p or a[to] > a[h]) continue;
res = max(dfs(to, v, k + 1, h), res);
}
return res;
}
void solve(){
int n;
cin>>n;
for(int i=1; i<=n; i++){
cin>>a[i];
p[i] = i;
mx[i] = i;
pos[a[i]] = i;
sz[i] = 1;
dp[i] = 0;
}
for(int i=1; i<n; i++){
int l, r;
cin>>l>>r;
q[l].pb(r);
q[r].pb(l);
}
for(int i=1; i<=n; i++){
vector<int> d;
int v = pos[i];
dp[v] = dfs(v, 0, 0, v);
}
cout<<dp[pos[n]]<<'\n';
}
int main(){
solve();
}
