#include <bits/stdc++.h>
using namespace std;
ifstream fin("asmax.in");
ofstream fout("asmax.out");
int n,s[20000],x,y,ans=-1000000000,use[20000];
vector <int> v[20000];
void dfs(int nod)
{
    use[nod]=1;
    for(auto it : v[nod])
        if(!use[it])
        {
            dfs(it);
            if(s[it]>0)
                s[nod]+=s[it];
        }
}
int main()
{
    fin>>n;
    for(int i=1;i<=n;i++)
        fin>>s[i];
    for(int i=1;i<n;i++)
    {
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1);
    for(int i=1;i<=n;i++)
        ans=max(ans,s[i]);
    fout<<ans;
    return 0;
}