#include <bits/stdc++.h>
#define pb push_back
using namespace std;
const int NMAX = 16000 + 5;
int n,i,cost[NMAX],a,b,ret=INT_MIN,sol[NMAX];
vector <int> g[NMAX];
bool sel[NMAX];
inline void dfs(int x)
{
    sel[x] = true;
    sol[x] += cost[x];
    for(int i = 0; i<g[x].size(); ++i)
        if (!sel[g[x][i]])
        {
            dfs(g[x][i]);
            if (sol[g[x][i]]>0)sol[x]+=sol[g[x][i]];
            ret = max(ret,sol[x]);
        }
}
int main()
{
    freopen("asmax.in","r",stdin);
    freopen("asmax.out","w",stdout);
    scanf("%d", &n);
    for (int i = 1; i<=n ; ++i)
        scanf("%d", &cost[i]);
    for (int i = 1; i<n; ++i)
    {
        scanf("%d %d\n", &a, &b);
        g[a].pb(b);
        g[b].pb(a);
    }
    dfs(1);
    printf("%d\n", ret);
    return 0;
}