///////////////////////////////////////////////////////////////////////////////////////////////
#include <bits/stdc++.h>
using namespace std;
// #define int long long
#define FAST_IO ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)
#define FILE_IO(x) freopen((string(x) + ".in").c_str(), "r", stdin); freopen((string(x) + ".out").c_str(), "w", stdout)
#define f first
#define s second
#define x1 x1qwer
#define y1 y1qwer
#define right right123
#define left left123
#define foreach(it, v) for (auto it : v)
#define rep(it, n) for (int it = 0; it < n; ++it)
#define forin(it, l, r) for (int it = l; it < r; ++it)
#define all(x) x.begin(), x.end()
typedef long long ll;
typedef unsigned long long ull;
typedef double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const double DINF = numeric_limits<double>::infinity();
const ll MOD = 1e9 + 7;
const double EPS = 1e-7;
ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
mt19937 mmtw_(MOD);
uniform_int_distribution<ll> rd_;
ll randomll() { return rd_(mmtw_);}
ll rnd(ll x, ll y) { return rd_(mmtw_) % (y - x + 1) + x; }
template <class T> T fact(T n) { if (n == 1) return 1; return n * fact(n - 1); }
////////////////////////////////////////////////////////////////////////////////////////////////
const int MAXN = 1e4 + 5;
const int MAXK = 105;
int n;
int a[MAXN];
bitset<MAXK> bs[MAXK];
vector<int> r[MAXK];
vector<int> g[MAXN];
vector<pair<int, int>> seg[MAXN];
void dfs(int v) {
for (auto to : g[v]) {
dfs(to);
}
rep(i, MAXK) {
bs[i].reset();
r[i].clear();
}
for (auto to : g[v]) {
for (auto it : seg[to]) {
r[it.f].push_back(it.s);
}
}
for (int left = MAXK - 1; left >= 1; --left) {
if (left == a[v]) {
bs[left] |= bs[left + 1];
bs[left].set(left);
} else {
for (auto right : r[left]) {
if (right < a[v] || left > a[v]) {
bs[left] |= bs[right + 1];
bs[left].set(right);
}
}
}
for (int right = left; right < MAXK; ++right) {
if (bs[left].test(right) && left <= a[v] && a[v] <= right) {
seg[v].push_back({left, right});
}
}
}
}
int main() {
FAST_IO;
cin >> n;
rep(i, n) {
cin >> a[i];
}
rep(i, n - 1) {
int p, q;
cin >> p >> q;
g[p - 1].push_back(q - 1);
}
dfs(0);
cout << seg[0].size() << endl;
}
