#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],mmin=INT_MIN;

void citire()
{
    in>>n;
    for(int i=1;i<=n;i++)
    {
        in>>v[i];
        mmin=max(mmin,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)
{
    dp[node]=v[node];
    for(auto x:lista[node])
    {
        if(x==tata) continue;
        dfs(x,node);
        if(dp[x]>0)
            dp[node]+=dp[x];
    }
}
int main()
{
    citire();
    dfs(1,1);/*
    if(dp[1]==0)
        out<<mmin;
    else*/
        out<<dp[1];
    return 0;
}