#include<iostream>
#include<fstream>
using namespace std;
ifstream in("sortaret.in");
ofstream out("sortaret.out");
int a[10000][10000],viz[100],n,m;
void dfs(int k)
{
     viz[k]=1;
     for(int i=1;i<=n;++i)
      if(a[k][i] && !viz[i])
       { out<<i<<" ";
             dfs(i);

       }
}


int main ()
{
    int i,x,y;

    in>>n>>m;

    for(i=1;i<=n;++i)
     { in>>x>>y;
      a[x][y]=1;
     }

      out<<1<<" ";
      dfs(1);

in.close();
out.close();

}