#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 i = 0; i < int(graf[nod].size()); i++ ){
        if( !viz[graf[nod][i]] ){
            dfs(graf[nod][i]);
            if( dp[graf[nod][i]] > 0 )
                dp[nod] += dp[graf[nod][i]];
        }
    }
}
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);
    out << dp[1];
    return 0;
}