#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
#include <stdio.h>
#include <ctype.h>
#include <cstdio>
#include <cstring>

using namespace std;

class OutParser {
private:
    FILE *fout;
    char *buff;
    int sp;

    void write_ch(char ch) {
        if (sp == 50000) {
            fwrite(buff, 1, 50000, fout);
            sp = 0;
            buff[sp++] = ch;
        } else {
            buff[sp++] = ch;
        }
    }


public:
    OutParser(const char* name) {
        fout = fopen(name, "w");
        buff = new char[50000]();
        sp = 0;
    }
    ~OutParser() {
        fwrite(buff, 1, sp, fout);
        fclose(fout);
    }

    OutParser& operator << (int vu32) {
        if (vu32 <= 9) {
            write_ch(vu32 + '0');
        } else {
            (*this) << (vu32 / 10);
            write_ch(vu32 % 10 + '0');
        }
        return *this;
    }

    OutParser& operator << (long long vu64) {
        if (vu64 <= 9) {
            write_ch(vu64 + '0');
        } else {
            (*this) << (vu64 / 10);
            write_ch(vu64 % 10 + '0');
        }
        return *this;
    }

    OutParser& operator << (char ch) {
        write_ch(ch);
        return *this;
    }
    OutParser& operator << (const char *ch) {
        while (*ch) {
            write_ch(*ch);
            ++ch;
        }
        return *this;
    }
};
class InParser {
private:
	FILE *fin;
	char *buff;
	int sp;

	char read_ch() {
		++sp;
		if (sp == 4096) {
			sp = 0;
			fread(buff, 1, 4096, fin);
		}
		return buff[sp];
	}

public:
	InParser(const char* nume) {
		fin = fopen(nume, "r");
		buff = new char[4096]();
		sp = 4095;
	}

	InParser& operator >> (int &n) {
		char c;
		while (!isdigit(c = read_ch()) && c != '-');
		int sgn = 1;
		if (c == '-') {
			n = 0;
			sgn = -1;
		} else {
			n = c - '0';
		}
		while (isdigit(c = read_ch())) {
			n = 10 * n + c - '0';
		}
		n *= sgn;
		return *this;
	}

	InParser& operator >> (long long &n) {
		char c;
		n = 0;
		while (!isdigit(c = read_ch()) && c != '-');
		long long sgn = 1;
		if (c == '-') {
			n = 0;
			sgn = -1;
		} else {
			n = c - '0';
		}
		while (isdigit(c = read_ch())) {
			n = 10 * n + c - '0';
		}
		n *= sgn;
		return *this;
	}
};
InParser fin("ciclueuler.in");
OutParser fout("ciclueuler.out");
int afis[500005],nr,n,m;
vector < pair <int,int> > v[100005];
void euler(int k)
{
    unsigned int x,i,j;
    for (i=0; i<v[k].size(); i++)
    {
        if (v[k][i].second==0)
        {
            x=v[k][i].first;
            v[k][i].second=1;
            for (j=0; j<v[x].size(); j++)
                if (v[x][j].first==k and v[x][j].second==0)
                {
                    v[x][j].second=1;
                    break;
                }
            euler(x);

        }

    }
    afis[++nr]=k;
}
int main()
{
    int i,j;
    fin>>n>>m;
    while (m!=0)
    {
        fin>>i>>j;
        v[i].push_back({j,0});
        v[j].push_back({i,0});
        m--;
    }
    euler(1);
    ///fout<<nr<<'\n';
    for (i=1; i<=nr; i++)
        fout<<afis[i]<<" ";
    return 0;
}