#include <fstream>
#include <vector>

using namespace std;

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

int n,MAX=-1005,cost[16005];
bool viz[16005];
vector <int> G[16005];

int dfs(int poz)
{
    viz[poz]=1;
    int sum=cost[poz];
    for(int i=0;i<G[poz].size();i++)
    if(viz[G[poz][i]]!=1)
    {
        int creanga;
        creanga=dfs(G[poz][i]);
        if(creanga+sum>sum)
            sum+=creanga;
    }
    if(sum>MAX)
        MAX=sum;
    return sum;
}

int main()
{
    fin>>n;
    for(int i=1;i<=n;i++)
        fin>>cost[i];
    for(int i=1;i<n;i++)
    {
        int a,b;
        fin>>a>>b;
        G[a].push_back(b);
        G[b].push_back(a);
    }
    int x=dfs(1);
    fout<<MAX;
    return 0;
}