//#pragma GCC optimize("Bismillahirrahmanirrahim")
//█▀█─█──█──█▀█─█─█
//█▄█─█──█──█▄█─█■█
//█─█─█▄─█▄─█─█─█─█
//Alllahuekber
//osmiyum
//23orz
//Sani buyuk Osman Pasa Plevneden cikmam diyor.
//FatihSultanMehmedHan
//YavuzSultanSelimHan
//AbdulhamidHan
//dört böler altı artı iki ama ne böler altı ne böler iki
//Başarı, Boş Duranın Hakkı Değil... Koşturanın Hakkıdır. Hakan?
//Ne yapayım, elimden gelen bu :(
//#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
#define int long long
#define pb push_back
#define ins insert
#define mid ((start+end)/2)
#define FOR for(int i=0;i<n;i++)
#define see2(x,y) cin>>x>>y
#define see3(x,y,z) cin>>x>>y>>z
#define ll long long
#define invalid (start>end || start>r || end<l || r<l)
#define fi first
#define se second
#define _ <<" "<<
#define bit (1<<i)
using namespace std;
typedef pair<int,int> pii;
typedef pair<int,pair<int,int>> piii;
const int INF=1e5+1;
const int nmax=1e5+1;
const int MOD=1e9+7;
const int big = 1e9;
void solve(){
int n;
cin>>n;
vector<vector<pii>> komsu(n+10,vector<pii>());
vector<int> v(n+10,-1);v[0]=0;
for(int i=0;i<n;i++){int a,b;cin>>a>>b;komsu[a].pb({b,i});komsu[b].pb({a,i});}
queue<int> q;q.push(0);
while(q.size()){
int node=q.front();q.pop();
for(auto go:komsu[node]){
if(~v[go.fi])continue;
v[go.fi]=v[node]^(1<<go.se);
q.push(go.fi);
}
}
cout<<(1<<(n-1))<<endl;
for(int i=0;i<(1<<n)-1;i++){
if(__builtin_popcount(i)%2)continue;
for(int j=0;j<=n;j++){cout<<(v[j]^i)<<" ";}cout<<endl;
}
}
int32_t main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
/* freopen("xxxxx.in", "r", stdin);
freopen("xxxxx.out", "w", stdout); */
int tt=1;
/* cin>>tt; */
while(tt--){
solve();
}
return 0;
}
