#include <fstream>
#include <algorithm>
#include <vector>

std::ifstream in("asmax.in");
std::ofstream out("asmax.out");

const int N = 16e3+1;
std::vector<int> g[N];
int v[N];
int dp[N];
bool visited[N];

void dfs(int i){
    visited[i] = 1;
    dp[i] = v[i];

    for(auto nod : g[i]){
        if(!visited[nod]){
            dfs(nod);
            dp[i] += std::max(0, dp[nod]);
        }

    }
}


int main(){
    int n;
    in>>n;
    for(int i=1;i<=n;++i){
        in>>v[i];
    }
    for(int i=0;i<n-1;++i){
        int a,b;
        in>>a>>b;
        g[a].push_back(b);
        g[b].push_back(a);
    }
    dfs(1);
    out<<dp[std::max_element(dp+1, dp+n+1)-dp];
    in.close();
    out.close();
    return 0;
}