#include <bits/stdc++.h>

using namespace std;

ifstream fin("asmax.in");
ofstream fout("asmax.out");
int n, ma, x, y, i;
int v[16002], r[16002];
vector<int> a[16002];

static inline void parc(int u, int x) {
    r[x] = v[x];
    for(auto it : a[x]) {
        if(it != u) {
            parc(x, it);
            if(r[it] > 0) r[x] += r[it];
        }
    }
}

int main() {
    fin >> n;
    for(i = 1; i <= n; i++) fin >> v[i];
    for(i = 1; i < n; i++) {
        fin >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }

    parc(0, 1);

    ma = INT_MIN;
    for(i = 1; i <= n; i++) ma = max(ma, r[i]);
    fout << ma;

    return 0;
}