#include <bits/stdc++.h>

using namespace std;
ifstream in("asmax.in");
ofstream out("asmax.out");
#define NMAX 16001
vector <int>g[NMAX];
int v[NMAX],d[NMAX],n;
bool vizitat[NMAX];
void dfs(int node){
    vizitat[node]=1;
    for(auto y:g[node])
        if(!vizitat[y]){
            dfs(y);
    d[node]=d[node]+max(d[y],0);
    }

}
int main()
{
    in>>n;
    for(int i=1;i<=n;i++)
        in>>d[i];
    int x,y;
    while(in>>x>>y){
        g[x].push_back(y);
        g[y].push_back(x);
        }
    int maxim=0;
    dfs(1);
    for(int i=1;i<=n;i++)
        maxim=max(d[i],maxim);
    out<<maxim;
    return 0;
}