#include <fstream>
#define dim 16001
#include <queue>
#include <vector>
#define INF 1 << 29
using namespace std;
ifstream fin("asmax.in");
ofstream fout("asmax.out");
vector <short int> G[dim];
queue <int> Q;
int n,a,b,nod,node,dp[dim],leg,Max,i;
void Dfs(int nod, int tata)
{
    for(int i=0;i<G[nod].size();i++)
    {
        if(G[nod][i]!=tata)
        {
            Dfs(G[nod][i],nod);
            if(dp[G[nod][i]]>0)
                dp[nod]+=dp[G[nod][i]];
        }
    }
}
int main()
{
    fin>>n;
    Max-=INF;
    for(i=1;i<=n;i++)
        fin>>dp[i];
    for(i=1;i<n;i++)
    {
        fin>>a>>b;
        G[a].push_back(b);
        G[b].push_back(a);
    }
    Dfs(1,-1);
    for(i=1;i<=n;i++)
        if(Max<dp[i])
            Max=dp[i];
    fout<<Max;
    return 0;
}