#include <cstdio>
#include <vector>

using namespace std;

const int nmx = 16002;

int n,cost[nmx],dp[nmx],maxim = -0x3f3f3f3f;
vector <int> g[nmx];

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

int dfs(const int nod, const int parinte) {
    dp[nod] = cost[nod];
    for(vector<int>::iterator it = g[nod].begin(); it != g[nod].end(); ++it)
        if(*it != parinte) {
            dfs(*it,nod);
            if(dp[*it] > 0)
                dp[nod] += dp[*it];
        }
    maxim = maxim > dp[nod] ? maxim : dp[nod];
}

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