#include <iostream>
#include <vector>
#include<cstdio>
using namespace std;
int v[16010],best[16010];
vector <int> graf[16010];
bool viz[16010];
void dfs(int x)
{
    viz[x]=1;
    best[x]=v[x];
    for(auto i : graf[x])
        if(!viz[i])
            {
                dfs(i);
                if(best[i]>0)
                    best[x]+=best[i];
            }
}

int main()
{
    freopen("asmax.in","r",stdin);
    freopen("asmax.out","w",stdout);
    int n,m,i,a,b;
    cin>>n;
    m=n-1;
    for(i=1;i<=n;i++)
        cin>>v[i];
    while(m--)
    {
        cin>>a>>b;
        graf[a].push_back(b);
        graf[b].push_back(a);
    }
    dfs(1);
    int max=best[1];
    for(i=2;i<=n;i++)
        if(best[i]>max)
            max=best[i];
    cout<<max;
    return 0;
}