#include <vector>
#include <algorithm>
#include <iostream>
#include <set>
#include <cmath>
#include <map>
#include <random>
#include <cassert>
#include <ctime>
#include <cstdlib>
#include <limits.h>
using namespace std;
vector<vector<pair<pair<int,int>,int>>> sub;
vector<vector<int>> adj;
vector<int> v;
void dfs (int curNode, int prevNode) {
vector<int> children;
vector<pair<pair<int,int>,int>> left, right;
for (int i: adj[curNode]) {
if (i == prevNode) {
continue;
}
dfs (i, curNode);
for (auto& p: sub[i]) {
if (p.first.first <= v[curNode] && v[curNode] <= p.first.second) {
continue;
}
if (p.first.first < v[curNode]) left.emplace_back(p);
else right.emplace_back(p);
}
}
map<int,int> dpL, dpR;
dpL[v[curNode]] = dpR[v[curNode]] = 1;
sort(left.begin(), left.end()); reverse(left.begin(), left.end());
for (auto& p: left) {
dpL[p.first.first] += dpL[p.first.second + 1] * p.second;
}
for (auto& p: right) {
dpR[p.first.second] += dpR[p.first.second - 1] * p.second;
}
map<pair<int,int>,int> myMap;
for (auto& l: dpL) {
for (auto& r: dpR) {
myMap[{l.first, r.first}] += l.second * r.second;
}
}
for (auto& p: myMap) {
if (p.second != 0) {
sub[curNode].push_back(p);
}
}
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int N;
cin >> N;
adj.resize(N);
v.resize(N);
for (int i = 0; i < N; i++) {
cin >> v[i];
v[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);
}
sub.resize(N);
dfs(0, -1);
int ans = 0;
for (auto& p: sub[0]) {
//cout << p.first.first << " " << p.first.second << " " << p.second << '\n';
ans += p.second;
}
cout << ans << '\n';
}
