#include <bits/stdc++.h>
#define Nmax 16005
using namespace std;
ifstream fin("asmax.in");
ofstream fout("asmax.out");
int n,a[Nmax],dp[Nmax];
vector <int> L[Nmax];
bitset <Nmax> used;
bitset <Nmax> fr;
inline void DFS(int nod)
{
    int i;
    dp[nod]=a[nod];
    used[nod]=1;
    for(i=0;i<L[nod].size();i++)
        if(!used[L[nod][i]])
        {
            DFS(L[nod][i]);
            if(dp[L[nod][i]]>0)dp[nod]+=dp[L[nod][i]];
        }
}
inline void Citire()
{
    int i,x,y;
    fin>>n;
    for(i=1;i<=n;i++)
        fin>>a[i];
    for(i=1;i<n;i++)
    {
        fin>>x>>y;
        fr[y]=1;
        L[x].push_back(y);
        L[y].push_back(x);
    }
    fin.close();
}

inline void Rezolvare()
{
    int i,ans;
    for(i=1;i<=n;i++)
        if(!fr[i]) DFS(i);
    ans=dp[1];
    for(i=2;i<=n;i++)
        ans=max(ans,dp[i]);
    fout<<ans<<"\n";
    fout.close();
}
int main()
{
    Citire();
    Rezolvare();
    return 0;
}