#include <bits/stdc++.h>
#define nmax 16002
using namespace std;
int n,d[nmax],dp[nmax];
vector <int> L[nmax];
bool viz[nmax];

void dfs(int nod)
{
    viz[nod]=1;
    dp[nod]=d[nod];
    for(unsigned int i=0;i<L[nod].size();i++)
    {
        if(viz[L[nod][i]]==0)
        {
            dfs(L[nod][i]);
            if(dp[L[nod][i]]>0)
                dp[nod]+=dp[L[nod][i]];
        }
    }
}

int main()
{
    int x,y,i;
    ifstream fin("asmax.in");
    fin>>n;
    for(i=1;i<=n;i++)
        fin>>d[i];
    for(i=1;i<n;i++)
    {
        fin>>x>>y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
    fin.close();
    dfs(1);
    x=dp[1];
    for(i=2;i<=n;i++)
        x=max(x,dp[i]);
    ofstream fout("asmax.out");
    fout<<x;
    fout.close();
    return 0;
}