#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ll long long
#define fr first
#define sc second
#define pb push_back
#define endl "\n"
#define all(x) x.begin(),x.end()
#define sp << " " <<
#define inf 1e9
#define N 100000
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
typedef tuple<int,int,int> tiii;
typedef pair<int,int> pii;
int dsu[N+5],d[N+5],a[N+5];
vector<int> g[N+5];
int find(int x){
if(dsu[x]<0)
return x;
return dsu[x]=find(dsu[x]);
}
int comb(int x,int y){
x=find(x);
y=find(y);
if(x==y)
return 0;
int t=d[x]+d[y];
d[x]=max(d[x],d[y]);
dsu[y]=x;
return t;
}
void solve(){
memset(dsu,-1,sizeof(dsu));
int n;
cin >> n;
vector<pii> v;
for(int i=1;i<=n;i++){
cin >> a[i];
d[i]=a[i];
v.pb({a[i],i});
}
sort(all(v));
for(int i=1;i<n;i++){
int x,y;
cin >> x >> y;
g[x].pb(y);
g[y].pb(x);
}
int ans=0;
for(auto [h,i]:v)
for(auto j:g[i])
if(a[j]<=h)
ans+=comb(i,j);
cout << ans << endl;
}
int32_t main(){
//~ freopen("a.txt","r",stdin);
//~ freopen("a.txt","w",stdout);
ios_base::sync_with_stdio(false);
cin.tie(NULL);cout.tie(NULL);
int test=1;
//~ cin >> test;
while(test--) solve();
}
