#include<bits/stdc++.h>
using namespace std;
int n;
struct lyz
{
	vector<int> son;
};
int find_root(int);
void dfs(int);vector<int> a,pre,dp1,dp0;vector<vector<int> > next;vector<bool> pd;
int main()
{
	//cin>>n;
	scanf("%d",&n);
	vector<vector<int> > ttm(n+1,vector<int>(1,0));
	next=ttm;
	//lyz ttm;
	pd.assign(n+1,false);
	dp0.assign(n+1,0);
	dp1.assign(n+1,0);
	//ttm.son.assign(1,0);
	a.assign(n+1,0);
	//next.resize(n+1,ttm);
	pre.assign(n+1,0);//next.assign(n+1,ttm);
	//vector <int>nex(n+1,vector<int>(1,0));
	//cout<<next[1].son.back();
	//for(int i=1;i<=n;i++) cout<<a[i];
	for(int i=1;i<=n;i++)
	{
		cin>>a[i];
		//next.son.push_back(0);
	}
	for(int i=1;i<=n-1;i++)
	{
		int temp1,temp2;
		scanf("%d%d",&temp1,&temp2);
		//cin>>temp1>>temp2;
		pd[temp2]=true;
		pre[temp1]=temp2;
		next[temp2].push_back(temp1);
	}
	int root=find_root(1);
/*	for(int i=1;i<=n;i++)
	{
		cout<<pd[i]<<' ';
	}*/
//	cout<<endl<<pre[4];
	dfs(root);
	cout<<max(dp1[root],dp0[root]);
	//cout<<root;
	
}
int find_root(int i)
{
	if(pre[i]==0) return i;
	else return find_root(pre[i]);
}
void dfs(int node)
{
	if(!pd[node])
		{
			//cout<<node<<' ';
			dp1[node]=a[node];
			dp0[node]=0;
			return;
		}
		else
	for(int i=1;i<next[node].size();i++)
	{
		/*if(pd[node])
		{
			cout<<1;
			dp[node][1]=a[node];
			dp[node][0]=0;
			return;
		}*/
		//else
		{
			dfs(next[node][i]);
			if(i==1) dp1[node]=a[node];
			dp1[node]=max(dp1[node],dp1[node]+dp0[next[node][i]]);
			//cout<<node<<' '<<dp1[node];
			//dp[node][0]=max(dp[node][0],)
			dp0[node]=max(max(dp0[node],dp0[node]+dp0[next[node][i]]),dp0[node]+dp1[next[node][i]]);
		//	cout<<' '<<dp0[node]<<endl;
		} 
	}
	
}