#include <fstream>
#import <algorithm>
#import <vector>
#import <set>
#import <stack>
using namespace std;
main()
{
    ifstream cin("asmax.in");
    ofstream cout("asmax.out");
    int n;
    cin>>n;
    vector<int>a(n+1),dp(n+1,0);
    for(int i=1;i<=n;i++)cin>>a[i];
    vector<vector<int>>g(n+1);
    for(int i=1;i<n;i++)
    {
        int x,y;
        cin>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    int rez=-2e9;
    auto dfs=[&](auto && dfs,int nod,int tata)->void
    {
        for(auto &c:g[nod])
        {
            if(c!=tata)
            {
                dfs(dfs,c,nod);
                dp[nod]+=max(0,dp[c]);
            }
        }
        dp[nod]+=a[nod];
        rez=max(rez,dp[nod]);
    };
    dfs(dfs,1,1);
    cout<<rez<<'\n';
}