#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
#define F first
#define S second
#define forn(i, n) for(int i = 0; i < n; ++i)
#define forbn(i, b, n) for(int i = b; i < n; ++i)
#define sz(v) (int)v.size()
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define all(v) v.begin(), v.end()
#define min3(a, b, c) min(a, min(b, c))
#define lc v << 1
#define rc (v << 1) + 1
typedef pair<int, int> ii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef long long ll;
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
template <class T> inline void mineq(T &a, T b) { a = min(a, b); }
template <class T> inline void maxeq(T &a, T b) { a = max(a, b); }
const int MX = 10 * 1000;
vi gr[MX];
int jokes[MX];
bitset<100> gl_gr[100];
vi att;
void dfs2(int node) {
att[node] = true;
for(int nb = gl_gr[node]._Find_first(); nb < sz(gl_gr[node]); nb = gl_gr[node]._Find_next(nb)) {
if(!att[nb])
dfs2(nb);
}
}
vii dfs(int node = 0) {
vii edges;
for(int nb: gr[node]) {
vii links = dfs(nb);
for(ii p: links) {
if(jokes[node] < min(p.F, p.S))
edges.eb(p.F - 1, p.S);
else if(jokes[node] > max(p.F, p.S))
edges.eb(p.S + 1, p.F);
}
}
att.assign(100, false);
forn(i, 100)
gl_gr[i].reset();
for(ii p: edges)
gl_gr[p.F][p.S] = 1;
dfs2(jokes[node]);
vi left, right;
forbn(l, 0, jokes[node] + 1) if(att[l]) left.pb(l);
forbn(r, jokes[node], 100) if(att[r]) right.pb(r);
edges.clear();
for(int l: left)
for(int r: right)
edges.eb(l, r);
return edges;
}
void solve() {
int n;
cin >> n;
forn(i, n) {
cin >> jokes[i];
jokes[i]--;
}
forn(_, n - 1) {
int a, b;
cin >> a >> b;
a--; b--;
gr[a].pb(b);
}
vii links = dfs(0);
cout << sz(links);
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
// freopen("triangles.in", "r", stdin);
// freopen("triangles.out", "w", stdout);
int t = 1;
// cin >> t;
while(t--) {
solve();
}
}
