#include <bits/stdc++.h>
#define N 16001

int valnod[N];

using namespace std;

vector<int> v[N];

bool marc[N];

int msum=-1001;

int best(int k){
    int q,sum=valnod[k],o;
    marc[k]=1;
    for(int i=0;i<v[k].size();i++){
        q=v[k][i];
        if(marc[q]==0)
        {
            o=best(q);
            if(o>0)
                sum+=o;
        }
    }
    msum=max(msum,sum);
    return sum;
}

int main()
{
    int n,a,b,i;
    FILE*fi,*fo;
    fi=fopen("asmax.in","r");
    fo=fopen("asmax.out","w");
    fscanf(fi,"%d",&n);
    for(i=1;i<=n;i++)
    {
        fscanf(fi,"%d",&valnod[i]);
    }
    for(i=0;i<n-1;i++){
        fscanf(fi,"%d%d",&a,&b);
        v[a].push_back(b);
        v[b].push_back(a);
    }
    best(1);
    fprintf(fo,"%d",msum);
    fclose(fi);
    fclose(fo);
    return 0;
}