#include <bits/stdc++.h>

using namespace std;

vector<vector<int>> v;

const int sz=16005;

int a[sz],ver[sz],dp[sz];

int dfs(int nod)
{
    ver[nod]=1;
    dp[nod]=a[nod];
    for(auto i:v[nod])
    {
        if(ver[i]==0)
        {
            dfs(i);
            if(dp[i]>0)
                dp[nod]+=dp[i];
        }
    }
    return dp[nod];
}

int main()
{
    ifstream cin("asmax.in");
    ofstream cout("asmax.out");
    int n;
    cin >> n;
    v.resize(n+5);
    for(int i=1;i<=n;i++)
    {
        cin >> a[i];
    }
    int x,y;
    for(int i=1;i<n;i++)
    {
        cin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1);
    int maxnr=0;
    for(int i=1;i<=n;i++)
    {
        if(dp[i]>maxnr)
            maxnr=dp[i];
    }
    cout << maxnr;
    return 0;
}