#include <iostream>
#include <algorithm>
#include <vector>
#include <list>

using namespace std;

#define MAXN 100005

list<int> sol;

class Muchie
{
public:
    int a;
    int b;
    bool folosit;

    Muchie(int a,int b)
    {
        this->a=a;
        this->b=b;
        folosit=false;
    }
};

vector<Muchie*> graf[MAXN];
int n,m;

void expand(int x)
{
    int nod=x;

    while(1)
    {
        while (graf[nod].size()>0 && graf[nod][graf[nod].size()-1]->folosit)
            graf[nod].pop_back();

        if(graf[nod].size()>0 && graf[nod][graf[nod].size()-1]->folosit)
        {
            muchie->folosit=true;
            graf[nod].pop_back();
            int vecin=muchie->a+muchie->b-nod;
        }
        else
            return;
    }
}

void euler()
{
    sol.push_back(1);
    it=list.begin();

    list<int>::iterator it;

    while(it!=list.end())
    {
        expand(*it);
        it++;
    }
}

int main()
{
    int i,a,b;
    cin>>n>>m;

    for(i=0;i<m;i++)
    {
        cin>>a>>b;
        //graf[a].push_back(b);
        //graf[b].push_back(a);
    }

    return 0;
}