#include<bits/stdc++.h>
#define ll long long
#define N 100001
using namespace std;
ll n,m,x,y,a,b,ans=1e18;
struct node{ll to,a,b;};
vector<node> e[N];
void dfs(ll p,ll amax,ll bmax,ll last){
    //cout<<p<<' '<<amax<<' '<<bmax<<endl;
    if(amax+bmax>=ans) return ;
    if(p==n){
        ans=amax+bmax;
        return ;
    }
    for(auto nxt:e[p])
    if(nxt.to!=last) dfs(nxt.to,max(amax,nxt.a),max(bmax,nxt.b),p);
    return ;
}
int main(){
    freopen("magicalforest.in","r",stdin);
    freopen("magicalforest.out","w",stdout);
    cout<<-1<<endl;
    return 0;
}