#include <bits/stdc++.h>
#define ff first
#define ss second
#define endl '\n'
using namespace std;
const long long INF = (long long) 1e18;
const int mod = (int) 1e9+7;
const int MAXN = (int) 3e5+5;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
ll n;
int joke[MAXN];
vector<int> adj[MAXN];
pii dfs(int v){
vector<pair<int, pii>> ls, gr;
vector<bool> can(101);
for(int j: adj[v]){
pii c = dfs(j);
if(joke[j] < joke[v]){
ls.push_back({joke[j], c});
}else if(joke[j] > joke[v])
gr.push_back({joke[j], c});
}
sort(ls.begin(), ls.end(), greater<pair<int, pii>>());
sort(gr.begin(), gr.end());
can[joke[v]] = 1;
for(auto &u: ls){
u.ss.ss = min(u.ss.ss, joke[v] - 1);
bool cn = 0;
for(int j = u.ff + 1; j <= u.ss.ss + 1; j++){
if(can[j]){
cn = 1;
break;
}
}
if(cn){
for(int j = u.ss.ff; j <= u.ff; j++)
can[j] = 1;
}
}
for(auto &u: gr){
u.ss.ff = max(u.ss.ff, joke[v] + 1);
bool cn = 0;
for(int j = u.ss.ff - 1; j < u.ff; j++){
if(can[j]){
cn = 1;
break;
}
}
if(cn){
for(int j = u.ff; j <= u.ss.ss; j++){
can[j] = 1;
}
}
}
int mn = 0, mx = 100;
while(!can[mn])
mn++;
while(!can[mx])
mx--;
return make_pair(mn, mx);
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr);cout.tie(nullptr);
#ifdef Local
freopen("C:/Users/Admin/Desktop/Yazilim/C/IO/int.txt","r",stdin);
freopen("C:/Users/Admin/Desktop/Yazilim/C/IO/out.txt","w",stdout);
#endif
cin>>n;
for(int i = 1; i <= n; i++)
cin>>joke[i];
for(int i = 0; i < n - 1; i++){
int a, b;
cin>>a>>b;
adj[a].push_back(b);
}
pii ans = dfs(1);
cout<<(joke[1] - ans.ff + 1) * (ans.ss - joke[1] + 1);
#ifdef Local
cout<<endl<<fixed<<setprecision(2)<<1000.0 * clock() / CLOCKS_PER_SEC<< " milliseconds ";
#endif
}
