#include<fstream>
#include<vector>
#include<stack>
using namespace std;

int N,M;
vector<int> G[50000];
vector<int> R[50000];
stack<int> S;

ifstream f("sortaret.in");
ofstream g("sortaret.out");

void Read()
{

    f>>N>>M;
    for(int i=0;i<M;i++)
    {
        int x,y;
        f>>x>>y;
        G[x].push_back(y);
    }
}

int IsLeaf(int x)
{
    return !G[x].size();
}

void TopologicalSort(int x)
{
    int i=-1;
    for(vector<int>::iterator it=G[x].begin();it!=G[x].end();it++)
    {
        i++;
        if(IsLeaf(*it))
        {
            S.push(*it);
        }
        else
        {
            TopologicalSort(*it);
            S.push(*it);
        }
    }
}

void Write()
{
    g<<1<<' ';
    while(!S.empty())
    {
        g<<S.top()<<" ";
        S.pop();
    }
    g<<'\n';
}

int main()
{
    Read();
    TopologicalSort(1);
    Write();

    return 0;
}