#include <bits/stdc++.h>

using namespace std;
const int NMAX=20000;
int rez=-1*INT_MAX;
bool vf[NMAX];
int dp[NMAX];
vector<int>v[NMAX];
void dfs(int nod)
{
    vf[nod]=true;
    for(auto i:v[nod])
    {
        if(vf[i]==false)
        {
            dfs(i);
            dp[nod]+=max(0,dp[i]);
        }

    }
    if(rez<dp[nod])
    {
        rez=dp[nod];
    }
}
int main()
{
    ifstream cin("asmax.in");
    ofstream cout("asmax.out");
    int n;
    cin>>n;
    for(int i=1;i<=n;i++)
    {
        int a;
        cin>>a;
        dp[i]=a;
    }
    for(int i=1;i<n;i++)
    {
        int a,b;
        cin>>a>>b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    dfs(1);
    cout<<rez;
    return 0;
}