#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ld long double
#define ull unsigned long long
#define pii pair<int,int>
#define pll pair<long long, long long>
#define fi first
#define se second
#define all(a) (a).begin(), (a).end()
#define pb push_back
#define lwb lower_bound
#define upb upper_bound
#define TASKNAME "NAME"
void init()
{
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
///freopen(TASKNAME".INP","r",stdin); freopen(TASKNAME".OUT","w",stdout);
}
const int SZ = 1e4+5, MAXM = 1e2+5;
const ll INF = INT_MAX / 2, MOD = 1e9+7, INFLL = 2e18;
const double epsilon = 1e-3;
int n, a[SZ];
vector<int> adj[SZ];
bitset<MAXM> dp[SZ][MAXM], b[MAXM];
void dfs(int u)
{
dp[u][a[u]][a[u]] = 1;
for(int v : adj[u])
{
dfs(v);
}
for(int i = 1; i <= 100; i++) b[i].reset();
for(int v : adj[u])
{
for(int i = 1; i <= 100; i++)
{
b[i] |= dp[v][i];
}
}
for(int i = 1; i <= 100; i++)
{
for(int j = i+1; j <= 100; j++)
{
if(b[i][j-1]) b[i] |= b[j];
}
}
for(int i = 1; i <= a[u]; i++)
{
for(int j = a[u]; j <= 100; j++)
{
if((i == a[u] || b[i][a[u] - 1]) && (j == a[u] || b[a[u]+1][j])) dp[u][i][j] = 1;
}
}
}
int main()
{
init();
cin >> n;
for(int i = 1; i <= n; i++)
{
cin >> a[i];
}
for(int i = 1; i < n; i++)
{
int u,v;
cin >> u >> v;
adj[u].pb(v);
}
dfs(1);
int res = 0;
for(int i = 1; i <= 100; i++)
{
res += dp[1][i].count();
}
cout << res;
}
