#include <bits/stdc++.h>
#define mod 9901

using namespace std;
ifstream fin("asmax.in");
ofstream fout("asmax.out");

int n,v[16002];
vector<int>L[16002];
bool viz[16002];
int dp[16002];
///dp[i] = costul subarborelui de suma maxima cu rad in i

void DFS(int nod)
{
    viz[nod]=1;

    for(auto it : L[nod])
        if(viz[it] == 0)
        {
            DFS(it);
            if(dp[it] > 0)
                dp[nod] += dp[it];
        }
}

int main()
{
    fin>>n;
    for(int i=1;i<=n;++i)
        fin>>v[i];
    for(int i=1;i<n;++i)
    {
        int x,y;
        fin>>x>>y;
        L[x].push_back(y);
        L[y].push_back(x);
    }

    for(int i=1;i<=n;++i)
        dp[i]=v[i];

    DFS(1);
    int rasp=-2e9;
    for(int i=1;i<=n;++i)
        rasp=max(rasp,dp[i]);
    fout<<rasp;

}