#include <iostream>
#include <fstream>
#include <vector>
#include <bitset>

using namespace std;

const int N = 100005;

int n, m,nc=0;
vector<int> a[N+1];
bitset <N+1> viz;
int sum[N+1];
ifstream in("asmax.in");
ofstream out("asmax.out");

void dfs(int x)
{
    //cout<<x<<"   ";
    viz[x]=1;
    for (auto y: a[x])
    {
        if (!viz[y])
        {
            dfs(y);
            if(sum[y]>0)
            sum[x]+=sum[y];
        }
    }
}

int main()
{
    in>>n;
    for(int i=1;i<=n;i++)
        in>>sum[i];
    for (int i=0; i<n-1; i++)
    {
        int x,y;
        in>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }

    dfs(1);
    int maxi=-10000;
    for(int i=1;i<=n;i++)
    {
        //cout<<sum[i]<<" ";
       maxi=max(maxi,sum[i]);
    }
    out<<maxi;
    return 0;
}