#include <cstdio>
#include <vector>
#include <iostream>

using namespace std;

const int NMAX = 16001;

vector<int> graf[NMAX];
int viz[NMAX],dp[NMAX];
int N;

void citire()
{
    scanf("%d",&N);
    for(int i=1;i<=N;i++)
        scanf("%d",&dp[i]);
    for(int i=1;i<N;i++)
    {
        int a,b;
        scanf("%d%d",&a,&b);
        graf[a].push_back(b);
        graf[b].push_back(a);
    }

}

void dfs(int curent,int prec)
{
    viz[curent]=1;
    for(vector<int>::iterator ii = graf[curent].begin();ii!=graf[curent].end();ii++)
        if(!viz[*ii])
            dfs(*ii,curent);

    for(vector<int>::iterator ii = graf[curent].begin();ii!=graf[curent].end();ii++)
        if(dp[*ii]>0 && *ii != prec)
            dp[curent]+=dp[*ii];
}


int main()
{
    freopen("asmax.in","r",stdin);
    freopen("asmax.out","w",stdout);
    citire();
    dfs(1,0);
    printf("%d",dp[1]);
    return 0;
}