#include<bits/stdc++.h>
#define pb push_back
#define mp make_pair
#define int long long
#define vi vector<int>
#define vvi vector<vector<int>>
#define pii pair<int, int>
#define vpii vector<pair<int, int>>
#define vc vector<char>
#define vb vector<bool>
#define mii map<int,int>
#define f0r(i,n) for(int i=0;i<n;i++)
#define FOR(i,k,n) for(int i=k;i<n;i++)
#define all(v) (v).begin(),(v).end()
#define rall(v) (v).rbegin(),(v).rend()
#define in(a) int a; cin>>a
#define in2(a,b) int a,b; cin>>a>>b
#define in3(a,b,c) int a,b,c; cin>>a>>b>>c
#define in4(a,b,c,d) int a,b,c,d; cin>>a>>b>>c>>d
#define vin(v,n); vi v(n); f0r(i,n){cin>>v[i];}
#define out(a) cout<<a<<'\n'
#define out2(a,b) cout<<a<<' '<<b<<'\n'
#define out3(a,b,c) cout<<a<<' '<<b<<' '<<c<<'\n'
#define out4(a,b,c,d) cout<<a<<' '<<b<<' '<<c<<' '<<d<<'\n'
#define pout(a) cout<<a.first<<' '<<a.second<<'\n'
#define vout(v) for(auto u : v){cout<<u<<' ';} cout<<endl
#define dout(a) cout<<a<<' '<<#a<<endl
#define dout2(a,b) cout<<a<<' '<<#a<<' '<<b<<' '<<#b<<endl
#define yn(x); if(x){cout<<"YES"<<'\n';}else{cout<<"NO"<<'\n';}
const int leg = 1e9 + 7;
const int mod = 998244353;
using namespace std;
const int mxn = 1e4 + 5;
vvi adj(mxn);
// const int mxr = 4955;
vector<bitset<mxn>> dp(mxn); int N;
vi typ(mxn);
void dfs(int node){
int col = typ[node];
// dout(col);
for(auto u : adj[node]){
dfs(u);
}
dp[node][100 * col + col] = 1;
FOR(l, 2, 101){
for(int i = max(col - l + 1, 0LL); i <= col; i++){
//from i to i + l - 1
// if(node == 0)out2(i, i + l - 1);
FOR(j, i, i + l - 1){
//[i, j], [j+1, i+l-1]
if(col <= j){
for(auto u : adj[node]){
if(dp[u][(j + 1) * 100 + i + l - 1] & dp[node][i * 100 + j])dp[node][i * 100 + i + l - 1] = 1;
}
}
else{
for(auto u : adj[node]){
if(dp[node][(j + 1) * 100 + i + l - 1] & dp[u][i * 100 + j])dp[node][i * 100 + i + l - 1] = 1;
}
}
}
}
}
// out2(node, dp[node].count());
}
signed main(){
ios::sync_with_stdio(false);
cin.tie(NULL);
//ifstream cin(".in");
//ofstream cout(".out");
in(n); N = n;
f0r(i,n){
cin>>typ[i]; typ[i]--;
}
f0r(i, n-1){
in2(a, b); a--; b--;
adj[a].pb(b);
}
dfs(0);
out(dp[0].count());
}
