#include <iostream>
#include <vector>

using namespace std;
int n;
const int MaxN = 1e5;
long long w[MaxN + 1];
long long ans;
vector<int> g[MaxN + 1];

void dfs(int root, int fa) {
for (int i = 0; i <
g[root].size(); ++i) {
int son = g[root][i];
if (son != fa) {
dfs(son, root);

if (w[son] > 0)
w[root] += w[son];
}
}
if (w[root] > ans)
ans = w[root];
}

void _cin() {
std::ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> n;
for (int i = 1; i <= n; ++i)
{
cin >> w[i];
}
for (int j = 0; j < n - 1; ++j) {
int v, u;
cin >> u >> v;

g[u].push_back(v);
g[v].push_back(u);
}
}

int main() {
_cin();
dfs(1, 0);
cout << ans << endl;
return 0;
}