#include <cstdio>
#include <vector>
#include <bitset>
#include <algorithm>

#define Nmax 16005
#define pb push_back
#define itr vector<int>::iterator

using namespace std;
vector<int> G[Nmax];
bitset<Nmax> used;
int N,v[Nmax],mm=-1<<20,maxim;


void read()
{
    scanf("%d",&N);
    for(int i = 1;i <= N;++i)
        scanf("%d",&v[i]),mm=max(mm,v[i]);
    int a,b;
    for(int i = 1;i < N; ++i)
    {
        scanf("%d%d",&a,&b);
        G[a].pb(b);
        G[b].pb(a);
    }
}

int DFS(int k)
{
    used[k] = 1;
    int sol = 0,cr;
    for(itr it = G[k].begin(); it != G[k].end(); ++it)
        if(!used[*it])
        {
            cr = DFS(*it);
            maxim = max(maxim,cr);
            sol += max(0,cr);
        }
    return max(sol+v[k],0);
}

void solve()
{
    int ans = DFS(1);
    maxim = max(maxim,ans);
    if(maxim == 0)
        printf("%d",mm);
    else
        printf("%d",maxim);
}

int main()
{
    freopen("asmax.in","r",stdin);
    freopen("asmax.out","w",stdout);

    read();
    solve();

    return 0;
}