#include <bits/stdc++.h>

using namespace std;

inline void Open(const string Name) {
    #ifndef ONLINE_JUDGE
        (void)!freopen((Name + ".in").c_str(), "r", stdin);
        (void)!freopen((Name + ".out").c_str(), "w", stdout);
    #endif
}

vector <int> Gr[16001];

bitset <16001> vis;

int val[16001], dad[16001], dp[16001];
int N, ans = INT_MIN, nod, root;

void dfs(int v) {
    vis[v] = 1, dp[v] = val[v];
    for(int to : Gr[v]) {
        if(vis[to])
            continue;

        dfs(to);
        dp[v] = max(dp[v], dp[v] + dp[to]);
    }
}

void solve() {
    cin >> N;
    for(int i = 1;i <= N;i++)
        cin >> val[i];

    for(int i = 1, a, b;i < N;i++) {
        cin >> a >> b;
        Gr[a].emplace_back(b), dad[b] = a;
    }

    for(int i = 1;i <= N;i++)
        if(!dad[i]) {
            root = i;
            break;
        }

    dfs(root);

    for(int i = 1;i <= N;i++)
        ans = max(ans, dp[i]);
    cout << ans;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    Open("asmax");

    int T = 1;
    for(;T;T--) {
        solve();
    }

    return 0;
}