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

#define FILEIN "asmax.in"
#define FILEOUT "asmax.out"
#define NMAX 16001

using namespace std;

int sol[NMAX];
int val[NMAX];
int viz[NMAX];
vector<int> A[NMAX];
int n,x,i,y;

void dfs(int node)
{
    int i;
    viz[node] = 1;
    for ( i = 0; i < A[node].size(); i++ )
    {
        if(!viz[A[node][i]])
        {
            dfs(A[node][i]);
            if(sol[A[node][i]] > 0)
                sol[node] += sol[A[node][i]];
        }
    }
}

int main()
{
    freopen(FILEIN,"r",stdin);
    freopen(FILEOUT,"w",stdout);
    scanf("%d", &n);
    for ( i = 1; i <= n; i++)
        scanf("%d", &sol[i]);
    for ( i = 1; i < n; i++)
    {
        scanf("%d %d", &x, &y);
        A[x].push_back(y);
        A[y].push_back(x);
    }
    dfs(1);
    sort(sol+1,sol+n+1);
    printf("%d\n",sol[n]);
    return 0;
}