/***************************************************************************/
/********************** LANG TU HAO HOA **********************************/
/***************************************************************************/
#include <bits/stdc++.h>
#define FOR(i, a, b) for (int i = (a); i <= (b); ++i)
#define FORD(i, a, b) for (int i = (a); i >= (b); --i)
#define pii pair<int, int>
#define sz(x) ((int) x.size())
#define PB push_back
#define PF push_front
#define MP make_pair
#define ll long long
#define F first
#define S second
#define maxc 1000000007
#define MOD 1000000007
#define base 107
#define eps 1e-6
#define pi acos(-1)
#define N 10004
#define V 102
#define task ""
#define remain(x) ((x > MOD) ? (x - MOD) : x)
using namespace std;
int n, c[N];
vector <int> ke[N], a[V];
vector <pii> dp[N];
bitset <V> dd[N][V];
void DFS(int u, int p)
{
for (auto v : ke[u])
{
if (v == p) continue;
DFS(v, u);
}
FOR(i, 1, 100) a[i].clear();
for (auto v : ke[u])
for (auto pa : dp[v])
a[pa.F].PB(pa.S);
FORD(L, 100, 1)
{
if (L == c[u])
{
dd[u][L] |= dd[u][L+1];
dd[u][L].set(L);
}
else
{
for (auto R : a[L])
if (L > c[u] || c[u] > R)
{
dd[u][L] |= dd[u][R+1];
dd[u][L].set(R);
}
}
FORD(R, 100, L)
if (dd[u][L].test(R) && L <= c[u] && c[u] <= R)
dp[u].PB(MP(L, R));
}
}
int main()
{
ios_base::sync_with_stdio(0); cin.tie(NULL); cout.tie(NULL);
//freopen(task".inp", "r", stdin);
//freopen(task".out", "w", stdout);
cin >> n;
FOR(i, 1, n) cin >> c[i];
FOR(i, 1, n-1)
{
int u, v; cin >> u >> v;
ke[u].PB(v);
ke[v].PB(u);
}
DFS(1, -1);
cout << sz(dp[1]);
return 0;
}
