#include<cstdio>
#include<vector>
using namespace std;
vector<int>L[20000];
int n,m,i,j,v[20000],smax=-2000000000,a,b,x[20000],z[20000];
FILE *f,*g;
void dfs(int nod){
    int i;
    x[nod]=1;
    z[nod]=v[nod];
    for(i=0;i<L[nod].size();i++){
        if(x[L[nod][i]]==0){
            dfs(L[nod][i]);
            if(z[L[nod][i]]>0)
                z[nod]+=z[L[nod][i]];
        }
    }
}
int main(){
    f=fopen("asmax.in","r");
    g=fopen("asmax.out","w");
    fscanf(f,"%d",&n);
    for(i=1;i<=n;i++){
        fscanf(f,"%d",&v[i]);
    }
    for(i=1;i<=n-1;i++){
        fscanf(f,"%d%d",&a,&b);
        L[a].push_back(b);
        L[b].push_back(a);
    }
    dfs(1);
    for(i=1;i<=n;i++){
        if(z[i]>smax)
            smax=z[i];
    }
    fprintf(g,"%d",smax);

    fclose(f);
    fclose(g);
    return 0;
}