#include <bits/stdc++.h>
using namespace std;
const int maxn=5005;
int n,u,v;
int arr[maxn], sz[maxn];
bool dp[maxn][maxn];
vector<int> adj[maxn];
bool temp[maxn];
void solve(int x, int p){
dp[x][1] = true; //must take self
sz[x] = 1;
for (auto u:adj[x]){
if (u==p) continue;
solve(u,x);
if (arr[u] > arr[x]){ //larger child
if (!(dp[u][arr[u]] || dp[u][arr[u] - arr[x]])){
for (int k = 0; k <= sz[x]; k++) dp[x][k] = false;
}//larger child not fulfulled, whole subtree cannot be fulfilled
for (int k = 0; k <= sz[x]; k++) temp[k] = dp[x][k];
//just copy over
}
if (arr[u] < arr[x]){ //smaller child
if (!dp[u][arr[u]]){
for (int k = 0; k <= sz[x]; k++) dp[x][k] = false;
}
//smaller child not fulfulled, whole subtree cannot be fulfilled
for (int k = 0; k <= sz[x]; k++){
temp[k] |= dp[x][k]; //don't take smaller child
temp[k + arr[u]] |= dp[x][k]; //take smaller child
}
}
if (arr[u] == arr[x]){ //equal child
for (int k = 0; k <= sz[x]; k++){
for (int l = 0; l <= sz[u]; l++){
temp[k + l] |= dp[x][k] && dp[u][l];
} //take some part of child
}
if (dp[u][arr[u]]){
for (int k = 0; k <= sz[x]; k++){
temp[k] |= dp[x][k];
} //dont take child
}
}
sz[x] += sz[u];
for (int k = 0; k <= sz[x]; k++){
dp[x][k] = temp[k]; //swap
temp[k] = 0; //reset
}
}
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cin>>n;
for (int i=1;i<=n;i++){
cin>>arr[i];
}
for (int i=1;i<n;i++){
cin>>u>>v;
adj[u].emplace_back(v);
adj[v].emplace_back(u);
}
solve(1,0);
cout<<(dp[1][arr[1]]?"YES":"NO");
return 0;
}
