#include <bits/stdc++.h>
#include "swap.h"
using namespace std;
using ll = long long;
#define pb emplace_back
#define AI(i) begin(i), end(i)
template<class T> bool chmin(T &a, T b) { return b < a && (a = b, true); }
template<class T> bool chmax(T &a, T b) { return a < b && (a = b, true); }
#ifdef KEV
#define DE(args...) kout("[ " + string(#args) + " ] = ", args)
void kout() { cerr << endl; }
template<class T, class ...U> void kout(T a, U ...b) { cerr << a << ' ', kout(b...); }
template<class T> void debug(T l, T r) { while (l != r) cerr << *l << " \n"[next(l)==r], ++l; }
#else
#define DE(...) 0
#define debug(...) 0
#endif
const int MAX_N = 300010, inf = 1e9 + 7;
int ok_t[MAX_N], wei[MAX_N];
struct dsu {
vector<int> sz, good, deg;
vector<vector<pair<int,int>>> g;
dsu(int n = 0) {
g.resize(n), sz.resize(n, 1), good.resize(n), deg.resize(n);
for (int i = 0;i < n;++i)
g[i] = {{-1, i}};
}
// I want things before time j
int F(int i, int j) {
int a = prev(upper_bound(AI(g[i]), make_pair(j+1, -1)))->second;
return i == a ? i : F(a, j);
}
int F(int i) { return i == g[i].back().second ? i : F(g[i].back().second); }
void M(int a, int b, int t) {
bool ok = max(++deg[a], ++deg[b]) > 2;
a = F(a), b = F(b);
if (a == b) {
chmin(ok_t[a], t);
return good[a] = true, void();
}
if (sz[a] < sz[b]) swap(a, b);
if (good[a] |= ok || good[b])
chmin(ok_t[a], t);
g[b].pb(t, a);
sz[a] += sz[b];
}
}D;
bool valid(int t, int a, int b) {
a = D.F(a, t), b = D.F(b, t);
if (a != b) return false;
return ok_t[a] <= t;
}
int n, m;
void init(int N, int M,
std::vector<int> U, std::vector<int> V, std::vector<int> W) {
n = N, m = M;
D = dsu(n);
vector<tuple<int,int,int>> alle;
for (int i = 0;i < m;++i) {
alle.pb(W[i], U[i], V[i]);
}
sort(AI(alle));
for (int i = 0;i < n;++i)
ok_t[i] = inf;
for (int i = 0;i < m;++i) {
auto [w, a, b] = alle[i];
wei[i] = w;
D.M(a, b, i);
}
}
int getMinimumFuelCapacity(int X, int Y) {
int l = 0, r = m-1, mid;
while (l < r) {
mid = l + r >> 1;
if (valid(mid, X, Y))
r = mid;
else
l = mid + 1;
}
return valid(l, X, Y) ? wei[l] : -1;
}
