#include <bits/stdc++.h>
#define mod 1000000007
#define int long long
#define dim 16002
using namespace std;
ifstream fin ("asmax.in");
ofstream fout("asmax.out");
int v[dim],dp[dim];
vector<int> a[dim];
bool viz[dim];

void dfs (int x)
{
    dp[x]=v[x];
    viz[x]=1;
    for (auto y:a[x])
    if (viz[y]==0)
    {
        dfs(y);
        if (dp[y]>0)
        dp[x]+=dp[y];
    }
}

int32_t main()
{
    int i,x,y,n;
    fin>>n;
    for(i=1;i<=n;i++)
        fin>>v[i];
    for (i=1;i<n;i++)
    {
        fin>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    dfs(1);
    int maxi=dp[1];
    for (i=2;i<=n;i++)
        maxi=max(maxi,dp[i]);
    fout<<maxi<<'\n';
    return 0;
}