#include <fstream>
#include <cstdio>
#include <vector>
#define Nmax 16001
using namespace std;

ofstream g("asmax.out");

int n,c[Nmax],mx;
bool uz[Nmax];
vector<int> V[Nmax];

int dfs(int nod)
{
    int nr=c[nod];
    uz[nod] = 1;
    for (int i=0;i<V[nod].size();i++)
    {
        if (!uz[V[nod][i]])
        {
            int x = dfs(V[nod][i]);
            if (x>0)
                nr+=x;
        }
    }
    if (nr>mx)
        mx=nr;
    return nr;
}


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

    scanf("%d",&n);
    for (int i=1;i<=n;i++)
        scanf("%d",&c[i]);

    for (int i=1;i<n;i++)
    {
        int x,y;
        scanf("%d%d",&x,&y);
        V[x].push_back(y);
        V[y].push_back(x);
    }

    dfs(1);

    g<<mx;
    return 0;
}