//DFS
#include<iostream>
//#include<cstdlib>
#include<stack>
using namespace std;
/*
8 7 1 5
1 2
1 3
2 3
2 4
3 5
4 6
7 8
*/
stack <int> st;
int n, m, dau, cuoi, *trace;
bool **a, *s;

void nhap(){
    cin>> n >> m >> dau >> cuoi;
    dau--; cuoi--;
    trace = new int [n];
    s =  new bool [n];
    a = new bool *[n];
    for( int i = 0; i < n; i++) a [i] = new bool [n];
    int u, v, i, j;
    for(i = 0; i < n; i++){
        s [i] = true;
        for(j = 0; j < n; j++) a [i] [j] = false;
    }
    for(i = 0; i < m; i++){
        cin>> u >> v;
        u-- ; v--;
        a [u][v] = true;
        a [v][u] = true;
    }
    trace [dau] = -1;
}

void DFS(){
    int u, i, j = 1;
    st.push(dau); s [dau] = false;
    do{
        u = st.top();
//      if(u == cuoi) return;
        for(i = 0; i < n; i++) if(s [i] && a [u][i]){
            s [i] = false;
            cout << i + 1 << " ";
            st.push(i);
            trace [i] = u;
            break;
        }
        if(i >= n) st.pop();
    }
    while(!st.empty());
}
/*
void res(){
    if(st.empty()) return;
    if(st.top() == dau){
        cout<< st.top()+1 <<" ";
        st.pop();
        return ;
    }
    int u = st.top();
    st.pop();
    res();
    cout<< u + 1 <<" ";
}
*/
void res(int i){
    if(trace [i] >= 0) res(trace [i]);
    cout<< i+1 <<" ";
}
int main(){
    nhap();
    cout << dau + 1 <<" can visit : " << dau + 1 << " ";
    DFS();
    cout<<endl;
    res(cuoi);
    delete []s;
    for(int i = 0; i < n; i++) delete []a[i];
    delete []a;
    delete []trace;
    return 0;
}