#include <bits/stdc++.h>
using namespace std;
int n;
vector<vector<int>> tree;
void encrypt() {
tree.resize(n+1);
for (int i = 1; i < n; i++) {
int u, v; cin >> u >> v;
tree[u].push_back(v);
tree[v].push_back(u);
}
int root = 0;
for (int i = 1; i < n; i++) {
if (tree[i].size() > tree[root].size()) root = i;
}
if (root < tree[root][0]) cout << 0 << endl;
else cout << 1 << endl;
for (auto nxt: tree[root]) cout << nxt << " ";
cout << endl;
}
void decrypt() {
string s; cin >> s;
int root = -1;
for (int i = 0; i < n-1; i++) {
int a, b; cin >> a >> b;
if (root == -1) {
if (s == "0") root = a;
else root = b;
}
cout << (a ^ b ^ root) << endl;
}
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
int p; cin >> p >> n;
if (p == 1) encrypt();
else decrypt();
return 0;
}
