#include <cstdio>
#include <vector>

using namespace std;

FILE*f=fopen("asmax.in","r");
FILE*h=fopen("asmax.out","w");

vector<int> v[16001];

int n,d[16001],m=-2000000;

bool p[16001];

void dfs ( int x ){
    p[x]=1;
    for ( int i=0;i<v[x].size();++i ){
        int y=v[x][i];
        if ( p[y]==0 ){
            dfs(y);
            if ( d[y]>0 ){
                d[x]+=d[y];
                if ( d[x]>m )m=d[x];
            }
        }
    }
}

int main()
{
    fscanf(f,"%d",&n);
    for ( int i=1;i<=n;++i )
        fscanf(f,"%d",&d[i]);
    for ( int i=1;i<n;++i ){
        int a,b;
        fscanf(f,"%d%d",&a,&b);
        v[a].push_back(b);
        v[b].push_back(a);
    }
    dfs(1);
    fprintf(h,"\n%d",m);
    return 0;
}