#include <cstdio>
#include <vector>

using namespace std;

const int nmx = 16002;

int n;
int cost[nmx];
int dp[nmx];
int maxim;
vector <int> g[nmx];

void citire()
{
    scanf("%d", &n);
    for(int i = 1; i <= n; ++i)
        scanf("%d", &cost[i]);
    for(int i = 1; i < n; ++i)
    {
        int nod1, nod2;
        scanf("%d %d", &nod1, &nod2);
        g[nod1].push_back(nod2);
        g[nod2].push_back(nod1);
    }
}

int dfs(int nod, int tata)
{
    dp[nod] = cost[nod];

    for(vector<int>::iterator it = g[nod].begin(); it != g[nod].end(); ++it)
    {
        if(*it == tata)
            continue;

        dfs(*it,nod);

        if(dp[*it] > 0)
            dp[nod] += dp[*it];
    }

    maxim = max(maxim,dp[nod]);
}

int main()
{
    freopen("asmax.in", "r", stdin);
    freopen("asmax.out", "w", stdout);
    citire();
    dfs(1,0);
    printf("%d\n", maxim);
    return 0;
}