#include <bits/stdc++.h>
using namespace std;
//#pragma GCC optimize ("O3")
//#pragma GCC target ("sse4")
#define endl "\n"
typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
template<class T, class T2> inline bool chkmax(T &x, const T2 &y) { return x < y ? x = y, 1 : 0; }
template<class T, class T2> inline bool chkmin(T &x, const T2 &y) { return x > y ? x = y, 1 : 0; }
const ll mod = 1e9 + 7;
template<class T> inline void fix(T &x) {if(x >= mod | x <= -mod) {x %= mod;} if(x < 0) {x += mod;}}
#define out(x) cout << __LINE__ << ": " << (#x) << " = " << (x) << endl
const int MAX_N = 1e4 + 10, MAX_VAL = 1e2 + 10;
bool dp[MAX_N][MAX_VAL][MAX_VAL];
int sz[MAX_N];
vector<int> g[MAX_N];
int arr[MAX_N];
vector<int> fake[MAX_VAL];
bool used[MAX_N];
void dfs(int x, int p) {
for(auto it : g[x]) {
if(it == p) {continue;}
dfs(it, x);
}
for(int i = 0; i < MAX_VAL; i ++) {
fake[i].resize(0);
}
for(auto it : g[x]) {
if(it == p) {continue;}
for(int i = 0; i < MAX_VAL; i ++) {
for(int j = i; j < MAX_VAL; j ++) if(dp[it][i][j]) {
if(i <= arr[x] && j >= arr[x]) {continue;}
if(i == arr[x] || j == arr[x]) {continue;}
if(i < arr[x]) {
fake[j].push_back(i - 1);
} else {
fake[i].push_back(j + 1);
}
}
}
}
for(int i = 0; i < MAX_VAL; i ++) {
used[i] = false;
}
vector<int> foundl, foundr;
queue<int> q;
q.push(arr[x] - 1);
q.push(arr[x] + 1);
used[arr[x] - 1] = true;
foundl.push_back(arr[x] - 1);
used[arr[x] + 1] = true;
foundr.push_back(arr[x] + 1);
while(q.front()) {
auto curr = q.front(); q.pop();
for(auto it : fake[curr]) {
if(!used[it]) {
used[it] = true;
if(it < arr[x]) {
foundl.push_back(it);
} else {
foundr.push_back(it);
}
q.push(it);
}
}
}
for(auto l : foundl) {
for(auto r : foundr) {
dp[x][l + 1][r - 1] = true;
}
}
}
signed main() {
ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
int n;
cin >> n;
for(int i = 1; i <= n; i ++) {
cin >> arr[i];
}
for(int i = 0; i < n - 1; i ++) {
int a, b;
cin >> a >> b;
g[a].push_back(b);
g[b].push_back(a);
}
dfs(1, 0);
int ans = 0;
for(int i = 0; i < MAX_VAL; i ++) {
for(int j = 0; j < MAX_VAL; j ++) {
ans += dp[1][i][j];
}
}
cout << ans << endl;
return 0;
}
