#include <bits/stdc++.h>
//#include "bits_stdc++.h"
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
#define endl '\n'
#define f first
#define s second
#define pb push_back
#define mp make_pair
#define lb lower_bound
#define ub upper_bound
#define input(x) scanf("%lld", &x);
#define input2(x, y) scanf("%lld%lld", &x, &y);
#define input3(x, y, z) scanf("%lld%lld%lld", &x, &y, &z);
#define input4(x, y, z, a) scanf("%lld%lld%lld%lld", &x, &y, &z, &a);
#define print(x, y) printf("%lld%c", x, y);
#define show(x) cerr << #x << " is " << x << endl;
#define show2(x,y) cerr << #x << " is " << x << " " << #y << " is " << y << endl;
#define show3(x,y,z) cerr << #x << " is " << x << " " << #y << " is " << y << " " << #z << " is " << z << endl;
#define all(x) x.begin(), x.end()
#define discretize(x) sort(x.begin(), x.end()); x.erase(unique(x.begin(), x.end()), x.end());
#define FOR(i, x, n) for (ll i =x; i<=n; ++i)
#define RFOR(i, x, n) for (ll i =x; i>=n; --i)
using namespace std;
//using namespace __gnu_pbds;
//#define ordered_set tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>
//#define ordered_multiset tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update>
typedef long long ll;
typedef long double ld;
typedef pair<ld, ll> pd;
typedef pair<string, ll> psl;
typedef pair<ll, ll> pi;
typedef pair<ll, pi> pii;
typedef pair<pi, pi> piii;
ll const MAXN = 10000, MAXV = 100;
ll n, v, e;
vector<ll> adj[10005];
bitset<105> dp[10005][105];
vector<pi> s[10005];
vector<ll> nxt[105];
ll val[10005];
void dfs(ll x)
{
for (ll i=1; i<=MAXV; ++i) nxt[i].clear();
for (ll u: adj[x]) dfs(u);
for (ll u: adj[x]) for (pi a: s[u]) nxt[a.f].pb(a.s);
for (ll i = MAXV; i>=1; --i)
{
if (i == val[x]) // {val[x]} U other pairs
{
dp[x][i] |= dp[x][i+1];
dp[x][i][i] = 1;
continue;
}
// pair U other pairs
for (ll u: nxt[i])
{
//show(u);
if (u < val[x] || i > val[x])
{
dp[x][i] |= dp[x][u+1];
dp[x][i][u] = 1;
//cout << dp[x][i] << endl;
}
}
}
for (ll i = 1; i<=val[x] ; ++i) for (ll j=val[x]; j<=MAXV; ++j) if (dp[x][i][j]) s[x].pb(mp(i, j));
//show(x);
//for (pi u: s[x]) show2(u.f, u.s);
}
int main()
{
input(n);
for (ll i=1; i<=n; ++i) input(val[i]);
for (ll i=0; i<n-1; ++i)
{
input2(v, e);
adj[v].pb(e);
}
dfs(1);
ll ans = s[1].size();
print(ans, '\n');
return 0;
}
