#include <bits/stdc++.h>
#define N 16005
using namespace std;
ifstream in("asmax.in");
ofstream out("asmax.out");

vector<int>lista[N];
int n,v[N],dp[N];

void citire()
{
    in>>n;
    for(int i=1;i<=n;i++) in>>v[i];
    for(int i=1;i<n;i++)
    {
        int x,y;
        in>>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]=v[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);
    out<<dp[1];
    return 0;
}