#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream f("asmax.in");
ofstream g("asmax.out");
const int maxn=16002;
const int inf=1<<30;
int N,c[maxn],dp[maxn],maxi=-inf;
bool x[maxn];
vector <int>G[maxn];
void dfs(int last,int nod)
{
    int sz,i;
    x[nod]=1;
    sz=G[nod].size();
    for (i=0;i<sz;i++)
        if (x[G[nod][i]]==0)
        {
            dfs(nod,G[nod][i]);
            if (dp[G[nod][i]]>0)
                dp[nod]+=dp[G[nod][i]];
        }
    maxi=max(maxi,dp[nod]);

}
int main()
{
    int i,x,y;
    f>>N;
    for (i=1;i<=N;i++)
        {f>>c[i];dp[i]=c[i];}
    for (i=1;i<N;i++)
    {
        f>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    dfs(0,1);
    g<<maxi;
}