#include <cstdio>
#include <set>
#include <vector>
#include <algorithm>
using namespace std;
FILE *f = fopen("ciclueuler.in","r");
FILE *g = fopen("ciclueuler.out","w");
int N,M;
vector<int> E;
multiset<int> G[100005];
void euler(int nod){
    while(!G[nod].empty()){
        int v = *G[nod].begin();
        G[nod].erase(G[nod].begin());
        G[v].erase(G[v].find(nod));
        euler(v);
    }
    E.push_back(nod);
}
int main()
{
    fscanf(f,"%d %d",&N,&M);
    for(int i = 1;i <= M;i++){
        int x,y;
        fscanf(f,"%d %d",&x,&y);
        G[x].insert(y);
        G[y].insert(x);
    }
    euler(1);
    E.pop_back();
    for(auto it:E){
        fprintf(g,"%d ",it);
    }
    fclose(f);
    fclose(g);
    return 0;
}