#include <bits/stdc++.h>
#define N 16005
using namespace std;
ifstream fin("asmax.in");
ofstream fout("asmax.out");
int n,i,a,b,mx,v[N],s[N];
vector<int> q[N];
void dfs(int p,int x)
{
    int i,y;
    s[x]=v[x];
    for(i=0;i<q[x].size();++i)
    {
       y=q[x][i];
       if(y!=p) {dfs(x,y);
       if(s[y]>0) s[x]+=s[y];}
    }
}
int main()
{
    fin>>n;
    for(i=1;i<=n;++i)
    {
        fin>>v[i];
    }
    for(i=1;i<n;++i)
    {
        fin>>a>>b;
        q[a].push_back(b);
        q[b].push_back(a);
    }
    dfs(0,1);
    for(i=1;i<=n;++i)
    {
        mx=max(mx,s[i]);
    }
    fout<<mx;
    return 0;
}