#include<bits/stdc++.h>
using namespace std;
ifstream f("asmax.in");
ofstream g("asmax.out");
#define N 100001
vector<int> t[N];
bool o[N];
int i,j,n,m=-16e6,v[N];
int D(int i)
{
    int j,k;
    for(o[i]=1,k=t[i].size(),j=0;j<k;++j)
        if(!o[t[i][j]]) {
            D(t[i][j]);
            if(v[t[i][j]]>0)
                v[i]+=v[t[i][j]];
        }
}
int main()
{
    for(f>>n,i=1;i<=n;i++)
        f>>v[i];
    for(;f>>i>>j;t[i].push_back(j),t[j].push_back(i));
    for(D(1),i=1;i<=n;++i)
        if(v[i]>m)
            m=v[i];
    return g<<m,0;
}