#include<bits/stdc++.h>
using namespace std;
#define ft first
#define sd second
typedef long long ll;
typedef vector<bool> veb;
typedef vector<ll> vel;
typedef vector<vel> vevel;
typedef vector<vevel> vevevel;
typedef vector<pair<ll,ll>> velp;
typedef vector<pair<bool,bool>> velb;
typedef vector<char> vec;
typedef map<ll,ll> mll;
typedef map<char,ll> mcl;
typedef map<ll,char> mlc;
typedef map<ll,bool> mlb;
typedef map<char,char> mcc;
typedef vector<pair<char,char>> vecp;
typedef priority_queue<ll> pql;
const ll mo = 1e9+7;
vel v;
vevel shu;
vel value;
int n;
ll initialize(ll x){///初始化
    value[x]=v[x];
    for(auto i:shu[x]){
        value[x]+= initialize(i);
    }
    return value[x];
}
bool bl;
ll ditui(ll x){
    ll sum1=0,sum=0;
    for(auto i:shu[x]){
        ll a=ditui(i);
        if(bl){
            sum+=a;
            sum1+=value[i]-a;
        }else{
            sum+=value[i]-a;
            sum1+=a;
        }
        bl=false;
    }
    if(v[x]>0){
        sum1+=v[x];
        if(sum1>sum){
            bl=true;
            return sum1;
        }else{
            bl= false;
            return sum;
        }
    }
    bl= false;
    return max(sum,sum1);
}
void slv(){
    cin>>n;
    v=value=vel(n+1);
    for(int i=1;i<=n;i++){
        cin>>v[i];
    }
    shu=vevel(n+1);
    veb b(n+1);
    for(int i=1;i<n;i++){
        int l,k;
        cin>>l>>k;
        shu[k].push_back(l);
        b[l]=true;
    }
    ll x;
    for(int i=1;i<=n;i++){
        if(!b[i]){
            x=i;
            break;
        }
    }
    initialize(x);
//    for(int i=1;i<=n;i++){
//        cout<<value[i]<<' ';
//    }
    cout<<ditui(x)<<"\n";
}
int main(){
    ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
    ll t=1;
//    cin>>t;
    while(t--){
        slv();
    }
    return 0;
}