#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <map>
#include <set>
#include <climits>
#include <cmath>
#include <fstream>
#include <queue>
#include <stack>
#include <iomanip>
#include <bitset>
//#include "molecules.h"
using namespace std;
#define ll long long
//cin.tie(0);ios_base::sync_with_stdio(0);
const int MAXN = 105;
int dp[MAXN][MAXN][MAXN];
vector<int> nums;
vector<int> adjList[MAXN];
int n;
void dfs(int src) {
bool temp[MAXN][MAXN];
bool cur[MAXN][MAXN];
for (int i = 0; i < MAXN; i++) {
for (int j = 0; j < MAXN; j++) {
temp[i][j] = false;
cur[i][j] = false;
}
}
for (auto i : adjList[src]) {
dfs(i);
}
temp[nums[src]][nums[src]] = true;
for (auto i : adjList[src]) {
for (int j = 0; j < MAXN; j++) {
for (int k = j; k < MAXN; k++) {
temp[j][k] |= dp[i][j][k];
}
}
}
for (int i = 0; i < MAXN; i++) {
for (int j = i; j < MAXN; j++) {
for (int k = i; k <= j; k++) {
if (i == j) {
cur[i][j] |= temp[i][j];
}
else if (k == j) {
cur[i][j] |= temp[i][j];
}
else if (temp[i][k] && temp[k + 1][j]) {
cur[i][j] |= true;
}
}
}
}
for (int i = 0; i < MAXN; i++) {
for (int j = i; j < MAXN; j++) {
if (i < nums[src] && nums[src] < j) {
dp[src][i][j] = (cur[i][nums[src] - 1] && cur[nums[src] + 1][j]);
}
if (i == nums[src] && j == nums[src]) {
dp[src][i][j] = true;
}
else if (i == nums[src]) {
dp[src][i][j] = cur[i + 1][j];
}
else if (j == nums[src]) {
dp[src][i][j] = cur[i][j - 1];
}
}
}
}
int main() {
cin >> n;
for (int i = 0; i < n; i++) {
int temp;
cin >> temp;
temp--;
nums.push_back(temp);
}
for (int i = 0; i < n - 1; i++) {
int a, b;
cin >> a >> b;
a--;
b--;
adjList[a].push_back(b);
}
dfs(0);
int ans = 0;
for (int i = 0; i < MAXN; i++) {
for (int j = 0; j < MAXN; j++) {
ans += dp[0][i][j];
}
}
cout << ans << endl;
}
