#include<stdio.h>
#include<algorithm>
#include<vector>
#define pb push_back
#define maxn 16005
#define inf 0x3f3f3f3f
using namespace std;

int n,sol=-inf;
int v[maxn],val[maxn],s[maxn];
vector<int> l[maxn];

void read()
{
    int x,y;
    scanf("%d",&n);
    for(int i=1;i<=n;i++) scanf("%d",&val[i]);
    for(int i=1;i<n;i++)
    {
        scanf("%d%d",&x,&y);
        l[x].pb(y); l[y].pb(x);
    }
}

void dfs(int k)
{
    v[k]=1; s[k]=val[k];
    for(unsigned int i=0;i<l[k].size();i++)
     if(!v[l[k][i]])
     {
         dfs(l[k][i]);
         if(s[l[k][i]]>0) s[k]+=s[l[k][i]];
     }
     sol=max(sol,s[k]);
}

int main()
{
    freopen("asmax.in","r",stdin);
    freopen("asmax.out","w",stdout);

    read();
    dfs(1);
    printf("%d",sol);

    fclose(stdin);
    fclose(stdout);
    return 0;
}