#include <iostream>
#include <iostream>
#include <vector>
#include <algorithm>
#include <limits>
#include <numeric>
#include <cstring>
#include <string>
#include <queue>
#include <set>
#include <cmath>
#include <fstream>
#include <cstdlib>
#include <map>
#define pb push_back
#define mp make_pair
#define INF numeric_limits<int>::max()
#define lsb(x) (-x)&x
#define int64 long long
using namespace std;
ifstream in("asmax.in");
ofstream out("asmax.out");
int n,val[16002],dp[16002],sol=-INF;
vector< vector<int> > tree;
void dfs(int x,int p)
{
    dp[x]=val[x];
    for(vector<int>::iterator it=tree[x].begin();it!=tree[x].end();it++)
    if(*it!=p)
    {
        dfs(*it,x);
        dp[x]+=max(dp[*it],0);
    }
    sol=max(sol,dp[x]);
}
int main()
{
    in>>n;
    tree=vector< vector<int> > (n+1);
    for(int i=1;i<=n;i++)
        in>>val[i];
    for(int i=1;i<n;i++)
    {
        int x,y;
        in>>x>>y;
        tree[x].pb(y);
        tree[y].pb(x);
    }
    dfs(1,0);
    out<<sol<<'\n';
    return 0;
}