static String solve ( ) {
  int N = sc . nextInt ( ) ;
  int L = sc . nextInt ( ) ;
  String [ ] G = new String [ N ] ;
  for ( int i = 0 ;
  i < N ;
  ++ i ) {
    G [ i ] = sc . next ( ) ;
  }
  String B = sc . next ( ) ;
  for ( int i = 0 ;
  i < N ;
  ++ i ) {
    if ( G [ i ] . equals ( B ) ) {
      return "IMPOSSIBLE" ;
    }
  }
  if ( L == 1 ) {
    return "? 0" ;
  }
  char [ ] p1 = new char [ L - 1 ] ;
  Arrays . fill ( p1 , '?' ) ;
  StringBuilder p2 = new StringBuilder ( ) ;
  for ( int i = 0 ;
  i < 49 ;
  ++ i ) {
    p2 . append ( ( char ) ( '0' + i % 2 ) ) ;
  }
  p2 . append ( '?' ) ;
  for ( int i = 0 ;
  i < 49 ;
  ++ i ) {
    p2 . append ( ( char ) ( '0' + ( i + 1 ) % 2 ) ) ;
  }
  return String . valueOf ( p1 ) + " " + p2 . toString ( ) ;
}

static String solve ( ) { int N = sc . nextInt ( ) ; int L = sc . nextInt ( ) ; String [ ] G = new String [ N ] ; for ( int i = 0 ; i < N ; ++ i ) { G [ i ] = sc . next ( ) ; } String B = sc . next ( ) ; for ( int i = 0 ; i < N ; ++ i ) { if ( G [ i ] . equals ( B ) ) { return " IMPOSSIBLE " ; } } if ( L == 1 ) { return " ? ▁ 0" ; } char [ ] p1 = new char [ L - 1 ] ; Arrays . fill ( p1 , ' ? ' ) ; StringBuilder p2 = new StringBuilder ( ) ; for ( int i = 0 ; i < 49 ; ++ i ) { p2 . append ( ( char ) ( '0' + i % 2 ) ) ; } p2 . append ( ' ? ' ) ; for ( int i = 0 ; i < 49 ; ++ i ) { p2 . append ( ( char ) ( '0' + ( i + 1 ) % 2 ) ) ; } return String . valueOf ( p1 ) + " ▁ " + p2 . toString ( ) ; }
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