#include <bits/stdc++.h>
#include <variant>
#include "islands.h"
using namespace std;
typedef int ll;
variant<bool, vector<int>> find_journey(int n, int m, vector<int> u, vector<int> v){
if(n==2){
ll a=-1, b=-1, c=-1;
for(ll i=0; i<m; i++){
if(u[i]==0){
if(a==-1) a=i;
else b=i;
}
else c=i;
}
if(b==-1 || c==-1) return false;
return vector<int>({a, c, b, a, c, b});
}
else if(m==n*(n-1)){
ll a=-1, b=-1, c=-1, d=-1, e=-1, f=-1;
for(ll i=0; i<m; i++){
if(u[i]==0 && v[i]==1) a=i;
if(u[i]==1 && v[i]==0) b=i;
if(u[i]==1 && v[i]==2) c=i;
if(u[i]==2 && v[i]==1) d=i;
if(u[i]==2 && v[i]==0) e=i;
if(u[i]==0 && v[i]==2) f=i;
}
return vector<int>({a, c, e, f, d, b, e, c, a, b, d, f});
}
else{
vector<vector<pair<ll, ll>>> g(n);
for(ll i=0; i<m; i++){
g[u[i]].push_back({v[i], i});
}
if(g[0].size()==2){
ll a=g[0][0].second, b=g[0][1].second;
ll a1, b1;
if(a%2==0) a1=a+1;
else a1=a-1;
if(b%2==0) b1=b+1;
else b1=b-1;
return vector<int>({a, a1, b, b1, a1, a, b1, b});
}
return false;
}
}
