#include <bits/stdc++.h>
#define int long long
#define pii pair<int, int>
#define ALL(v) (v).begin(), v.end()
using namespace std;
const int maxn = 1e6 + 5;
const int mod = 1e9 + 7;
const int oo = 1e18;
const int logg = 19;
const int base = 31;
int n, a[maxn], pre[maxn], ans = 0;
set<int> S[maxn];
vector<int> adj[maxn];
void dfs(int u, int p){
    pre[u] = pre[p] ^ a[u];
    S[u].insert(pre[u]);
    bool del = false;
    for(int v : adj[u]){
        if(v == p) continue;
        dfs(v, u);
        if(del) continue;
        bool check = false;
        if(S[u].size() < S[v].size()){
            for(int x : S[u]){
                if(S[v].count(x ^ a[u])){
                    del = true;
                    break;
                }
            }
        }
        else{
            for(int x : S[v]){
                if(S[u].count(x ^ a[u])){
                    check = true;
                    break;
                }
            }
        }
        if(check){
            del = true;
        }
        else{
            if(S[u].size() < S[v].size()){
                S[u].swap(S[v]);
            }
            for(int x : S[v]){
                S[u].insert(x);
            }
        }
    }
    if(del){
        ans++;
        S[u].clear();
    }
}
signed main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	//freopen("dincpath.inp", "r", stdin);
	//freopen("dincpath.out", "w", stdout);
	cin >> n;
	for(int i = 1; i <= n; i++){
        cin >> a[i];
	}
	for(int i = 1; i < n; i++){
        int u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
	}
    dfs(1, 0);
    cout << ans;
	return 0;
}