#include<bits/stdc++.h>
#define mod 1000000007
#define inf 0x3f3f3f3f
#define bit(x,i)(((x)>>(i))&1)
#define FAST ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
using namespace std;
ifstream fin("asmax.in");
ofstream fout("asmax.out");
//const long long int mare=1LL*1000000000000000000;
const int mare=1000000000;
int T,n,m,ok,x,y,i,j,c,aux,start,maxx,minn;
int st,dr,mij,contor,suma,poz,numar;
int viz[16005],dp[16005],val[16005];
vector<int> G[16005];
void dfs(int k)
{
    viz[k]=1;
    dp[k]=val[k];
    for(int l=0;l<G[k].size();l++)
    {
        if(!viz[G[k][l]])
        {
            dfs(G[k][l]);
            if(dp[G[k][l]]>0)
                dp[k]+=dp[G[k][l]];
        }
    }
}
int main()
{
    fin>>n;
    for(i=1;i<=n;i++)
    {
        fin>>val[i];
        dp[i]=-mare;
    }
    for(i=1;i<n;i++)
    {
        cin>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    dfs(1);
    maxx=-mare;
    for(i=1;i<=n;i++)
    {
        if(maxx<dp[i])
            maxx=dp[i];
    }
    fout<<maxx;
    return 0;
}