#include "swap.h"
#include <bits/stdc++.h>
using namespace std;
#define OPTM ios_base::sync_with_stdio(0); cin.tie(0);
#define INF int(1e9+7)
#define ln '\n'
#define ll long long
#define ull unsigned long long
#define ui unsigned int
#define us unsigned short
#define FOR(i,s,n) for (int i = s; i < n; i++)
#define FORR(i,n,s) for (int i = n; i > s; i--)
#define FORX(u, arr) for (auto u : arr)
#define PB push_back
#define in(v,x) (v.find(x) != v.end())
#define F first
#define S second
#define PII pair<int, int>
#define PLL pair<ll, ll>
#define UM unordered_map
#define US unordered_set
#define PQ priority_queue
#define ALL(v) v.begin(), v.end()
const ll LLINF = 1e18+1;
const int MAXN = 3e5+10, LOG = 21;
int n,m;
vector<int> v[MAXN];
vector<pair<int,PII>> e;
int p[MAXN], sz[MAXN], x[MAXN], deg[MAXN], p1[MAXN];
int jump[MAXN][LOG], depth[MAXN];
bool good[MAXN];
int cur;
int finds(int a) {
if (p[a] != a) p[a] = finds(p[a]);
return p[a];
}
void unite(int a, int b, int w) {
int oa = a, ob = b;
a = finds(a);
b = finds(b);
deg[oa]++; deg[ob]++;
if (a != b) {
p[a] = p[b] = p1[a] = p1[b] = cur;
v[cur].PB(a);
v[cur].PB(b);
sz[cur] += sz[a]+sz[b];
x[cur] = w;
if (good[a] || good[b]) good[cur] = 1;
if (deg[oa] >= 3 || deg[ob] >= 3) good[cur] = 1;
cur++;
}
else {
if (good[a]) return;
good[a] = 1;
x[a] = w;
}
}
void dfs(int s, int pa) {
FORX(u,v[s]) {
if (u == pa) continue;
depth[u] = depth[s]+1;
dfs(u,s);
}
}
int lca(int a, int b) {
if (depth[a] < depth[b]) swap(a,b);
FORR(j,LOG-1,-1) {
if (jump[a][j] && depth[jump[a][j]] >= depth[b]) {
a = jump[a][j];
}
}
if (a == b && good[a]) return a;
FORR(j,LOG-1,-1) {
if (jump[a][j] != jump[b][j]) {
a = jump[a][j];
b = jump[b][j];
}
}
a = p1[a];
if (good[a]) return a;
FORR(j,LOG-1,-1) {
if (jump[a][j] && !good[jump[a][j]]) a = jump[a][j];
}
a = p1[a];
return a;
}
void init(int N, int M,
std::vector<int> U, std::vector<int> V, std::vector<int> W) {
n = N; m = M;
FOR(i,0,m) e.PB({W[i],{U[i]+1,V[i]+1}});
sort(ALL(e));
cur = n+1;
FOR(i,1,MAXN) {
p[i] = p1[i] = i;
sz[i] = 1;
}
FORX(u,e) {
unite(u.S.F, u.S.S, u.F);
}
dfs(cur-1,-1);
FOR(i,1,cur) jump[i][0] = p1[i];
FOR(j,1,LOG) {
FOR(i,1,cur) jump[i][j] = jump[jump[i][j-1]][j-1];
}
}
int getMinimumFuelCapacity(int a, int b) {
a++; b++;
int anc = lca(a,b);
if (!good[anc]) return -1;
return x[anc];
}
