#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define X first
#define Y second
#define ALL(v) v.begin(), v.end()
#define pb push_back
#define SZ(a) ((int)a.size())

const int N = 1e5 + 5;

int A[N];
int dp[N][2];
vector<int> v[N];

void dfs(int i, int f) {
    vector<int> chd;
    for (int x : v[i])
        if (x != f) {
            dfs(x, i); 
            chd.pb(x);
        }
    if (!SZ(chd)) {
        dp[i][0] = A[i];
        dp[i][1] = !A[i];
        return;
    }
    int s = 0;
    for (int j : chd)
        s += dp[j][0];
    vector<int> tmp;
    for (int j : chd)
        tmp.pb(dp[j][1] - dp[j][0]);
    sort(ALL(tmp), greater<int>());
    int fg = 0;
    dp[i][0] = s + A[i];
    for (int x : tmp) {
        fg = !fg;
        s += x;
        dp[i][fg] = max(dp[i][fg], s + (A[i] ^ fg));
    }
}

int main() {
    ios::sync_with_stdio(0), cin.tie(0);
    int n;
    cin >> n;
    for (int i = 1; i <= n; i++)
        cin >> A[i];
    for (int i = 1; i < n; i++) {
        int a, b;
        cin >> a >> b;
        v[a].pb(b);
        v[b].pb(a);
    }
    dfs(1, 1);
    cout << max(dp[1][0], dp[1][1]) << endl;
}