public static void main ( String omkar [ ] ) throws Exception {
  BufferedReader infile = new BufferedReader ( new InputStreamReader ( System . in ) ) ;
  StringTokenizer st = new StringTokenizer ( infile . readLine ( ) ) ;
  int N = Integer . parseInt ( st . nextToken ( ) ) ;
  ArrayList < Thing > ls = new ArrayList < Thing > ( ) ;
  for ( int i = 0 ;
  i < 2 * N - 1 ;
  i ++ ) {
    st = new StringTokenizer ( infile . readLine ( ) ) ;
    int a = i + 2 ;
    for ( int b = 1 ;
    b < a ;
    b ++ ) {
      int v = Integer . parseInt ( st . nextToken ( ) ) ;
      ls . add ( new Thing ( a , b , v ) ) ;
    }
  }
  Collections . sort ( ls ) ;
  HashSet < Integer > seen = new HashSet < Integer > ( ) ;
  int [ ] res = new int [ 2 * N + 1 ] ;
  for ( Thing t : ls ) {
    if ( seen . contains ( t . a ) || seen . contains ( t . b ) ) continue ;
    seen . add ( t . a ) ;
    seen . add ( t . b ) ;
    res [ t . a ] = t . b ;
    res [ t . b ] = t . a ;
  }
  StringBuilder sb = new StringBuilder ( ) ;
  for ( int i = 1 ;
  i <= 2 * N ;
  i ++ ) sb . append ( res [ i ] + " " ) ;
  System . out . println ( sb ) ;
}

public static void main ( String omkar [ ] ) throws Exception { BufferedReader infile = new BufferedReader ( new InputStreamReader ( System . in ) ) ; StringTokenizer st = new StringTokenizer ( infile . readLine ( ) ) ; int N = Integer . parseInt ( st . nextToken ( ) ) ; ArrayList < Thing > ls = new ArrayList < Thing > ( ) ; for ( int i = 0 ; i < 2 * N - 1 ; i ++ ) { st = new StringTokenizer ( infile . readLine ( ) ) ; int a = i + 2 ; for ( int b = 1 ; b < a ; b ++ ) { int v = Integer . parseInt ( st . nextToken ( ) ) ; ls . add ( new Thing ( a , b , v ) ) ; } } Collections . sort ( ls ) ; HashSet < Integer > seen = new HashSet < Integer > ( ) ; int [ ] res = new int [ 2 * N + 1 ] ; for ( Thing t : ls ) { if ( seen . contains ( t . a ) || seen . contains ( t . b ) ) continue ; seen . add ( t . a ) ; seen . add ( t . b ) ; res [ t . a ] = t . b ; res [ t . b ] = t . a ; } StringBuilder sb = new StringBuilder ( ) ; for ( int i = 1 ; i <= 2 * N ; i ++ ) sb . append ( res [ i ] + " ▁ " ) ; System . out . println ( sb ) ; }
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