#include <bits/stdc++.h>
using namespace std;
int cost[100005];
vector<int> adj[100005];
set<int> subtree[100005];
int ans;
void dfs(int n, int p) {
subtree[n].insert(n);
for (auto i:adj[n]) {
if (i != p) {
dfs(i, n);
auto tmp = subtree[i];
if (tmp.size() > subtree[n].size()) swap(tmp, subtree[n]);
for (auto x:tmp) subtree[n].insert(x);
}
}
}
set<int> cur_subtree;
void dfs2(int n, int p) {
for (auto i:adj[n]) {
if (i != p and cost[i] < cost[n]) {
//max in that subtree
auto itr = subtree[i].end();
itr--;
ans += *itr+n;
}
}
if (cost[p] < cost[n]) {
auto itr = cur_subtree.end();
itr--;
ans += *itr+n;
}
cur_subtree.insert(n);
for (auto i:adj[n]) {
if (i != p) {
dfs2(i, n);
}
}
cur_subtree.erase(n);
}
int main() {
int n; cin >> n;
for (int i = 0; i < n; i++) cin >> cost[i];
for (int i = 0; i < n-1; i++) {
int x, y; cin >> x >> y;
x--; y--;
adj[x].push_back(y);
adj[y].push_back(x);
}
ans = 0;
dfs(0, -1);
dfs2(0, -1);
cout << ans;
}
