#include<bits/stdc++.h>
using namespace std;
#define task "a"
#define se second
#define fi first
#define ll long long
#define ii pair<ll, ll>
const long mxN = 2e5 + 7;
int n, h[mxN], par[mxN][30], a[mxN];
ll dsu[mxN];
vector<int> w[mxN];
void DFS(int j)
{
h[j] = h[par[j][0]] + 1;
for (int i = 1; i <= 20; i++)
par[j][i] = par[par[j][i - 1]][i - 1];
for (int i : w[j])
{
if (h[i])
continue;
par[i][0] = j;
DFS(i);
}
}
ll LCA(int u, int v)
{
ll res = h[u] + h[v];
if (h[u] < h[v])
swap(u, v);
for (int i = 20; i >= 0; i--)
{
if (h[par[u][i]] >= h[v])
u = par[u][i];
}
if (u == v)
return res - h[u] * 2;
for (int i = 20; i >= 0; i--)
{
if (par[u][i] != par[v][i])
{
u = par[u][i];
v = par[v][i];
}
}
u = par[u][0];
return res - h[u] * 2;
}
int Find(int j)
{
if (dsu[j] <= 0)
return j;
else
return dsu[j] = Find(dsu[j]);
}
void Union(int u, int v)
{
v = Find(v);
dsu[u] = min(dsu[u], dsu[v] - LCA(u, v));
dsu[v] = u;
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
//freopen(task".INP", "r", stdin);
//freopen(task".OUT", "w", stdout);
cin >> n;
for (int i = 1; i <= n; i++)
cin >> a[i];
for (int i = 1; i < n; i++)
{
int u, v;
cin >> u >> v;
u = a[u];
v = a[v];
w[u].push_back(v);
w[v].push_back(u);
}
DFS(1);
for (int i = 1; i <= n; i++)
{
for (int j : w[i])
{
if (j < i)
Union(i, j);
}
}
cout << -dsu[n];
}
