#include <iostream>
using namespace std;
int
father[101], x, y, recordf[101], ancestor;
void
__read__()
{
cin >> x >> y;
int
a, b;
while( cin >> a >> b )
father[a] = b;
}
void
__ca__()
{
int f = x;
while( f )
{
recordf[f] = true;
f = father[f];
}
f = y;
while( !recordf[f] )
f = father[f];
ancestor = f;
}
void
__erg1__( int q )
{
if( q != ancestor )
{
cout << q << " ";
__erg1__( father[q] );
}
if( q == ancestor )
cout << q << " ";
}
void
__erg2__( int p )
{
if( p != ancestor )
{
__erg2__( father[p] );
cout << p << " ";
}
}
int
main()
{
__read__();
__ca__();
__erg1__( x );
__erg2__( y );
cout << endl;
return 0;
}