#include "bits/stdc++.h"
using namespace std;
const int N = 20;
vector <int> g[N];
int main(){
ios::sync_with_stdio(0);
cin.tie(0);
int n;
cin >> n;
for (int i = 0;i < n;i++){
int a,b;
cin >> a >> b;
g[a].push_back(b);
g[b].push_back(a);
}
vector <int> in(n+1,-1),p(n+1);
queue <int> q;
int l = 0;
in[0] = l;
q.push(0);
l++;
while (!q.empty()){
int a = q.front();
q.pop();
for (int b : g[a]){
if (~in[b])
continue;
in[b] = l++;
p[in[b]] = in[a];
q.push(b);
}
}
vector <vector <int>> v;
v.push_back({0,1});
for (int i = 1;i < n;i++){
int k = v.size();
for (int j = 0;j < k;j++){
v.push_back({v[j]});
for (auto &x : v.back()){
x ^= 1^(1<<i);
}
}
for (auto &x : v){
x.push_back(x[p[i+1]]^(1<<i));
}
}
cout << v.size() << "\n";
for (auto &x : v){
for (int i = 0;i <= n;i++){
cout << x[in[i]] << " ";
}
cout << "\n";
}
}
