#include <cstdio>
#include <vector>

using namespace std;

vector< vector<int> >g(16010);

int v[16010];
bool viz[16010];
int s;

void dfs(int node)
{
    int i;
    viz[node]=true;
    for(i=0; i<g[node].size(); i++)
    {
        if(viz[g[node][i]]==false)
        {
            dfs(g[node][i]);
            if(v[g[node][i]]>0)
                v[node]+=v[g[node][i]];
        }
    }
    if(v[node]>s)
        s=v[node];
}

int main()
{
    freopen("asmax.in","r",stdin);
    freopen("asmax.out","w",stdout);
    int i,n,node,x,y;
    scanf("%d",&n);
    node=1;
    for(i=1; i<=n; i++)
    {
        scanf("%d",&v[i]);
        if(v[i]>v[node])
            node=i;
    }

    for(i=1; i<=n-1; i++)
    {
        scanf("%d%d",&x,&y);
        g[x].push_back(y);
        g[y].push_back(x);
    }
    s=v[node];
    dfs(node);
    printf("%d",s);
    return 0;
}