//BFS
#include<iostream>
#include<queue>
using namespace std;

queue<int> qu;
bool **a, *s;
int *trace, dau, cuoi, n, m;

void nhap(){
    cin>> n >> m >> dau >> cuoi;
    dau-- ; cuoi-- ;
    a = new bool*[n];
    s = new bool [n];
    trace = new int [n];
    for(int i = 0; i < n; i++) a [i] = new bool [n];

    for(int i = 0; i < n; i++){
        s [i] = true;
        for(int j = 0 ; j < n ; j++) a [i][j] = false;
    }

    int u, v;
    for(int i = 0; i < m ; i++){
        cin>> u >> v;
        u--; v--;
        a [u][v] = true;
        a [v][u] = true;
    }

    trace [dau] = -1;
}

void BFS(){
    qu.push(dau);
    s [dau] = false;
    int u, i;
    do{
        u = qu.front();
        for(i = 0 ; i < n ; i++) if(s [i] && a [u][i]){
            s [i] = false;
            trace [i] = u;
            cout << i + 1 << " ";
            qu.push(i);
        }
        qu.pop();
    }
    while(!qu.empty());
}

void res(int i){
    if(trace[i] >= 0) res(trace [i]);
    cout<< i + 1 <<" ";
}

int main(){
    nhap();
    cout<< dau + 1<< " can visit : " << dau + 1 << " ";
    BFS();
    cout<<endl;
    res(cuoi);
    delete []s;
    delete []trace;
    for(int i = 0; i < n ; i++) delete []a [i];
    delete []a;
}