#include <bits/stdc++.h>
using namespace std;
ifstream f("asmax.in");
ofstream g("asmax.out");
int n,x,y,i,sol=-1<<30,dp[1<<14],v[1<<14];
bool viz[1<<14];
vector <int> V[1<<14];
void dfs(int x)
{
    viz[x]=1;
    dp[x]=v[x];
    for(int i=0;i<V[x].size();++i)
        if(!viz[V[x][i]])
    {
        dfs(V[x][i]);
        dp[x]=max(dp[x],dp[x]+dp[V[x][i]]);
    }
    sol=max(sol,dp[x]);
}
int main()
{
    f>>n;
    for(i=1;i<=n;++i) f>>v[i];
    for(i=1;i<n;++i)
    {
        f>>x>>y;
        V[x].push_back(y);
        V[y].push_back(x);
    }
    dfs(1);
    g<<sol;
    return 0;
}