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

using namespace std;

ifstream fin("asmax.in");
ofstream fout("asmax.out");

const int NMAX = 16001;

int val[NMAX];
int dp[NMAX];
vector < int > Ad[NMAX];
int N;

void DP( int nod, int parent ){

    dp[nod] = val[nod];
    for( int i = 0; i < Ad[nod].size(); ++i ){
        int w = Ad[nod][i];
        if( w != parent ){
            DP( w, nod );
            if( dp[w] > 0 ) dp[nod] += dp[w];
        }
    }
}
int main()
{
    fin >> N;

    for( int i = 1; i <= N; ++i )
        fin >> val[i];

    int x, y;
    for( int i = 1; i < N; ++i ){
        fin >> x >> y;
        Ad[x].push_back( y );
        Ad[y].push_back( x );
    }

    DP( 1, 0 );

    int vmax = -1000;
    for( int i = 1; i <= N; ++i )
        vmax = max( vmax, dp[i] );

    fout << vmax << '\n';
    return 0;
}