#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5;
int n, v, a, b;
pair<int, int> arr[N];
long long ans;
vector<int> graph[N];
vector<pair<int, int>> edges;
bool vis[N];
struct DSU{
int par[N], stsize[N], stmax[N];
DSU(){
for(int i = 1; i < N; i++) par[i] = i, stsize[i] = 1;
}
int setfind(int a){
if(par[a] == a) return a;
else return par[a] = setfind(par[a]);
}
int setunion(int a, int b){
int sum = 0;
a = setfind(a); b = setfind(b);
if(a != b){
sum = stmax[a] + stmax[b];
if(stsize[b] > stsize[a]) swap(a, b);
stsize[a] += stsize[b];
par[b] = par[a];
stmax[a] = max(stmax[a], stmax[b]);
}
return sum;
}
};
DSU dsu;
int main(){
ios_base::sync_with_stdio(false);cin.tie(NULL);
cin >> n;
for(int i = 1; i <= n; i++){
cin >> arr[i].first;
arr[i].second = i;
}
for(int i = 0; i < n - 1; i++){
cin >> a >> b;
graph[a].push_back(b); graph[b].push_back(a);
}
for(int i = 1; i <= n; i++) dsu.stmax[i] = arr[i].first;
sort(arr + 1, arr + n + 1, greater<pair<int, int>>());
for(int i = 1; i <= n; i++){
v = arr[i].second;
for(auto e : graph[v]){
if(!vis[e]) edges.push_back({v, e});
}
vis[v] = true;
}
reverse(edges.begin(), edges.end());
for(auto e : edges) ans += dsu.setunion(e.first, e.second);
cout << ans;
}
