#include <bits/stdc++.h>
using namespace std;
#define TRACE(x) cerr << __LINE__ << ": " << #x << " = " << x << endl
#define _ << " _ " <<
template<class> struct is_container : false_type {};
template<class... Ts> struct is_container<vector<Ts...>> : true_type {};
template<class... Ts> struct is_container<map<Ts...>> : true_type {};
template<class... Ts> struct is_container<unordered_map<Ts...>> : true_type {};
template<class... Ts> struct is_container<set<Ts...>> : true_type {};
template<class... Ts> struct is_container<unordered_set<Ts...>> : true_type {};
template<class... Ts> struct is_container<multiset<Ts...>> : true_type {};
template<class... Ts> struct is_container<unordered_multiset<Ts...>> : true_type {};
template<class T, class = typename enable_if<is_container<T>::value>::type>
ostream& operator<<(ostream &o, T x) {
int f = 1;
o << "{";
for (auto y : x) {
o << (f ? "" : ", ") << y;
f = 0;
}
return o << "}";
}
template<class T, class U>
ostream& operator<<(ostream &o, pair<T, U> x) {
return o << "(" << x.first << ", " << x.second << ")";
}
#define fi first
#define se second
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<ll> vll;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
int n;
cin >> n;
vector<vi> e(n + 1);
for (int i = 0; i < n; i++) {
int x, y;
cin >> x >> y;
e[x].push_back(y);
e[y].push_back(x);
}
vi ord(n + 1, -1), p(n + 1);
int t = 0;
queue<int> Q({0});
ord[0] = t++;
while (!Q.empty()) {
int x = Q.front();
Q.pop();
for (int y : e[x]) {
if (ord[y] != -1) continue;
ord[y] = t++;
p[ord[y]] = ord[x];
Q.push(y);
}
}
vector<vi> sol = {{0, 1}};
for (int i = 1; i < n; i++) {
int k = sol.size();
for (int j = 0; j < k; j++) {
sol.push_back(sol[j]);
for (auto& x : sol.back())
x ^= 1 ^ (1 << i);
}
for (auto& v : sol)
v.push_back(v[p[i + 1]] ^ (1 << i));
}
cout << sol.size() << '\n';
for (auto& v : sol) {
for (int i = 0; i <= n; i++)
cout << v[ord[i]] << ' ';
cout << '\n';
}
return 0;
}
