#include<bits/stdc++.h>
#define maxn 16005
using namespace std;

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

int n;
vector<int>lista[maxn];
int val[maxn],dp[maxn];

void citire()
{
    fin>>n;
    for(int i=1;i<=n;i++)
        fin>>val[i];
    int x,y;
    for(int i=1;i<n;i++)
    {
        fin>>x>>y;
        lista[x].push_back(y);
        lista[y].push_back(x);
    }
}

void dfs(int node,int tata)
{
    for(auto x: lista[node])
        if(x!=tata)
            dfs(x,node);

    dp[node]=val[node];
    for(auto x:lista[node])
    {
        if(x==tata) continue;
        dp[node]+=dp[x];
    }
    dp[node]=max(dp[node],0);
}

int main()
{
    citire();
    dfs(1,1);
    fout<<dp[1];
    return 0;
}