#include <bits/stdc++.h>
using namespace std;
#define ll long long
const int MAXN = 1e5 + 5;
vector<int> g[MAXN];
const int INF = 1e9;
int n;
ll dp[MAXN][2], val[MAXN];
void dfs(int u, int p) {
// cerr << u << '\n';
dp[u][0] = dp[u][1] = 0;
if (val[u] != 0) dp[u][val[u] - 1] = INF;
for (int v : g[u]) {
if (v != p) {
dfs(v, u);
if (dp[u][0] < INF) {
dp[u][0] += min(dp[v][1] + 1, dp[v][0]);
}
if (dp[u][1] < INF) {
dp[u][1] += min(dp[v][0] + 1, dp[v][1]);
}
}
}
}
void initialize(int N, vector<int> A, vector<int> B) {
for (int i = 0; i < N - 1; i++) {
g[A[i]].emplace_back(B[i]);
g[B[i]].emplace_back(A[i]);
// cerr << A[i] << ' ' << B[i] << '\n';
}
}
int cat(int v) {
val[v] = 2;
dfs(1, 1);
return (min(dp[1][0], dp[1][1]) < INF ? min(dp[1][0], dp[1][1]) : -1);
}
int dog(int v) {
val[v] = 1;
dfs(1, 1);
return (min(dp[1][0], dp[1][1]) < INF ? min(dp[1][0], dp[1][1]) : -1);
}
int neighbor(int v) {
val[v] = 0;
dfs(1, 1);
return (min(dp[1][0], dp[1][1]) < INF ? min(dp[1][0], dp[1][1]) : -1);
}
