#include <bits/stdc++.h>

using namespace std;
ifstream in("asmax.in");
ofstream out("asmax.out");
const int NMAX = 16001;
vector <int> graf[NMAX];
int dp[NMAX], cost[NMAX];
bool viz[NMAX];
void dfs( int nod ){
    viz[nod] = true;
    dp[nod] = cost[nod];
    for( int vecin: graf[nod]){
        if( !viz[vecin] ){
            dfs(vecin);
            if( dp[vecin] > 0 )
                dp[nod] += dp[vecin];
        }
    }
}
int main()
{
    int n, a, b;
    in >> n;
    for( int i = 1; i <= n; i++ )
        in >> cost[i];
    for( int i = 0; i < n-1; i++ ){
        in >> a >> b;
        graf[a].push_back(b);
        graf[b].push_back(a);
    }
    dfs(1);
    int maxi = -10000000;
    for( int i = 1; i <= n; i++ )
        if( dp[i] > maxi )
            maxi = dp[i];
    out << maxi;
    return 0;
}