#include "swap.h"
#include <bits/stdc++.h>
using namespace std;
#include <vector>
#define all(x) x.begin() , x.end()
int n , m;
vector<int> u , v , w;
int mx = 0;
struct LCA{
vector<int> anc[20] , dep;
void init(vector<vector<int>> &adj , int n){
for (auto &j : anc) j.resize(n);
dep.resize(n);
dfs(0 , -1 , adj);
}
void dfs(int node , int par , vector<vector<int>> &adj){
for (auto i : adj[node]){
if (i == par) continue;
dep[i] = dep[node] + 1;
anc[0][i] = node;
for (int j = 1 ; j < 20 ; j++){
anc[j][i] = anc[j-1][anc[j-1][i]];
}
dfs(i , node , adj);
}
}
int jump(int u , int k){
for (int j = 19 ; j >= 0 ; j--){
if (k & (1<<j)) u = anc[j][u];
}
return u;
}
int lca(int u , int v){
if (dep[u] > dep[v]) swap(u , v);
v = jump(v , dep[v] - dep[u]);
if (u == v) return u;
for (int j = 19 ; j >= 0 ; j--){
if (anc[j][u] != anc[j][v]) u = anc[j][u], v = anc[j][v];
}
return anc[0][u];
}
};
LCA l;
void init(int N, int M,vector<int> U, vector<int> V, vector<int> W) {
n = N , m = M , u = U , V = v , w = W;
if (m != n-1) return;
vector<vector<int>> adj(N);
for (int i = 0 ; i < M ; i++) adj[U[i]].push_back(V[i]),adj[V[i]].push_back(U[i]);
l.init(adj , N);
}
int getMinimumFuelCapacity(int X, int Y) {
if (m != n-1) return -1;
int c = l.lca(X , Y);
if (c != X && c != Y && l.dep[c]) return 0;
else return -1;
}
