#include <fstream>
#include <vector>

using namespace std;

const int N=16005;

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

vector <int> G[N];
int a[N], dp[N], sol=-0x3f3f3f3f;

void solve(int x, int pred)
{
    dp[x]=a[x];
    for(auto p: G[x])
    {
        if(p!=pred)
        {
            solve(p, x);
            if(dp[p]>0) dp[x]+=dp[p];
        }
    }
    if(dp[x]>sol) sol=dp[x];
}

int main()
{
    int n, i, x, y;
    fin>>n;
    for(i=1;i<=n;i++) fin>>a[i];
    for(i=1;i<n;i++)
    {
        fin>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    solve(1, 0);
    fout<<sol;
    fin.close();
    fout.close();
}