#include <iostream>
#include <vector>
#include <cstring>
using namespace std;
typedef pair<int, int> ii;
typedef vector<int> vi;
typedef vector<ii> vii;
vector<vii> g;
int N, T, M;
int m[30][(1<<12)][(1<<12)];
int solve(int c, int w, int d);
int mouse(int c, int w, int d){
int ret = 0;
for(int x=0; x<g[c].size(); x++){
if(!((1<<g[c][x].second)&w)&&!((1<<g[c][x].second)&d))
ret = max(ret, solve(g[c][x].first, w, d));
}
if(ret==0)
ret = solve(c, w, d);
return ret;
}
int solve(int c, int w, int d){
cout << c << endl;
if(c==T)
return 0;
if(m[c][w][d]!=-1&&m[c][w][d]!=-2)
return m[c][w][d];
int ret = 1e9;
if(m[c][w][d]!=-2){
m[c][w][d] = -2;
ret = mouse(c, w, d);
} else {
return -1;
}
for(int x=1; x<N; x++){
cout << x << endl;
if(d&(1<<x)){
ret = min(ret, mouse(c, w, d-(1<<x)));
}
ret = min(ret, mouse(c, w|(1<<x), d));
}
return m[c][w][d] = ret;
}
int main(){
cin>>N>>T>>M;
g.assign(N+1, vii());
int A, B;
for(int n=1; n<N; n++){
cin>>A>>B;
g[A].push_back({B, n});
g[B].push_back({A, n});
}
memset(m, -1, sizeof(m));
cout << solve(M, 0, 0) << endl;
return 0;
}
