#include<cstdio>
#include<vector>
#define INF 999999999
using namespace std;
FILE *f,*g;
int n,i,x,y,rez,v[16001],s[16001];
vector<int>l[16001];
void dfs(int x)
{
    s[x]=1;
    for(int i=0;i<l[x].size();++i)
    if(s[l[x][i]]==0)
    {
        dfs(l[x][i]);
        if(v[l[x][i]]>0)
        v[x]+=v[l[x][i]];
    }
    rez=max(rez,v[x]);
}
int main()
{
    f=fopen("asmax.in","r");
    g=fopen("asmax.out","w");
    rez=-INF;
    fscanf(f,"%d",&n);
    for(i=1;i<=n;++i)
    fscanf(f,"%d",&v[i]);
    for(i=1;i<n;++i)
    {
        fscanf(f,"%d%d",&x,&y);
        l[x].push_back(y);
        l[y].push_back(x);
    }
    dfs(1);
    fprintf(g,"%d\n",rez);
    return 0;
}